In 2010, NHL commissioner Gary Bettman was all about calming fears.

At his state of the league address in Chicago, he stated that the NHL was growing, albeit "not as strong perhaps in terms of the speed of growth that we were seeing and would like to continue to see as it was before the economic downturn." He said the Coyotes were staying in Arizona, the Hurricanes weren't leaving Raleigh, North Carolina, and the Islanders were safe in New York. (Ironically, no one asked about the Atlanta Thrashers.) He defended the idea of multiple outdoor games in a season, which the NHL was attempting for the first time. He called the 2010 Vancouver Olympics a "mixed bag" for the NHL, because apparently some things never change.

About a decade later, the NHL is in a much different place. Revenues for the 2017-18 season were $4.86 billion, up from $2.9 billion in 2009-10. The action on the ice in the NHL has arguably never been better, thanks to rules changes that emphasized speed and an influx of elite offensive talent to exploit them. Relocation talk has quieted, while two new expansion teams were added. Things are, by and large, pretty good.

It's not a utopia. The NHL remains plagued with player safety issues, part of an ongoing identity crisis for a league built on bloody rivalries that have become much more pallid. There's debate about everything from video reviews to the playoff format. There's still much work to be done to grow the game.

But the NHL did a lot of growing in the past 10 years.

Below are 10 sweeping changes and trends in the NHL as this decade nears its close. Keep in mind that this is an NHL-centric list, so it doesn't cover landmark moments like the U.S. women's national team fighting for equality and winning Olympic gold, or the historic formation of two professional women's leagues. There's plenty to the story of hockey in the past decade beyond the league.

Here's a look back at how the NHL changed in the past decade, and a look ahead at what will happen next for the league. It's going to be a fascinating next 10 years.

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Offense surges; fighting disappears

There are many theories why there are more goals being scored in the NHL, but the fact remains that we're witnessing an offensive upswing. Bruce Bennett/Getty Images

What happened: The change wasn't immediate. In 2008-09, the average goals per team in the NHL was 2.91. It would actually take the league until 2017-18 to surpass that mark (2.97), as part of a four-season uptick in offense. Then, in 2018-19, the NHL broke through with a 3.01 goals-per-team average; excluding the post-lockout anomaly of 2005-06, it was the best offensive season the NHL had seen since Mario Lemieux led the league with 161 points and teams averaged 3.14 goals in 1995-96.

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What led to the goal-scoring outburst? There were plenty of theories, including subtle rules enforcement changes for slashing and net-front defense and improvements in special-teams scoring. But it may have been as simple as the perfect confluence of offensive-friendly systems arriving as an influx of spectacularly creative young talents -- Connor McDavid, Auston Matthews, Jack Eichel, Patrik Laine among them -- arrived on the scene.

As pucks flew into the net with renewed regularity, fists flying between players continued a steep decline. In 2008-09, there were 734 fights in the NHL. That number dropped every season of the following decade all the way down to 224 fights in 2018-19, a nadir for the league. In 2008-09, 41.4 percent of regular-season games had a fight. Last season, just 15.3 percent of games had one.

One of the reasons John Scott's unlikely election to the 2016 All-Star Game resonated with fans was because he was one of the last traditional enforcers left in the NHL. It was a moment to celebrate a role that had been slowly eliminated from teams, and the cult status of the players whose particular set of skills was no longer needed.

What happens next: Offensive numbers will continue to climb in the short term, until teams begin to course-correct with more defensive systems. It's an inevitable circle of life in the NHL: Scoring goes up, then it goes down, and then the league changes or reinforces its rules to balloon goal scoring again.

Fighting won't see the same boomerang effect, continuing to decline precipitously. "No, I don't ever see it reversing," former NHL pugilist Matthew Barnaby told ESPN last month. "It's the way teams are being built. And having coached junior, it's not a part of that culture anymore, with all the rules in place."

The Department of Player Safety

Tom Wilson has become quite familiar with the Department of Player Safety. AP Photo/Nick Wass

What happened: In 2011, future Hockey Hall of Famer Brendan Shanahan was deputized by Bettman to head up the new Department of Player Safety, which would oversee supplemental discipline for on-ice incidents. But Shanahan didn't simply want to hand out suspensions. His initial aim was twofold: Educate players on the proper way to play the modern game, using video explanations of suspensions to break down what was and wasn't allowed; and target those repeat offenders whom the NHL was suspending with frequency.

Under Shanahan, Stephane Quintal and current director George Parros, the Department of Player Safety has policed the NHL effectively but not without controversy, as cries of favoritism and inconsistency have dogged it for years. The players' ability to appeal suspensions of six or more games to a neutral arbitrator further complicated things. But the number of catastrophic hits to the head, and annual offenders, has dropped during the department's era.

What happens next: Parros is eventually succeeded by another player who competed on the edge of legality, but the department adds new voices in players who were better known for taking injurious hits than delivering them.

The NHL makes the neutral arbitration process, in which it has taken a few losses, an issue in the next collective bargaining talks.

The 2013 CBA

The type of deal that Roberto Luongo signed with the Canucks is expressly forbidden in the NHL's current CBA. Jeff Vinnick/Getty Images

What happened: If there's a collective bargaining agreement expiring and Gary Bettman is the commissioner, you know what happened: a lockout, in this case spanning 113 days and forcing the cancellation of 510 games. But after the dust settled and the pain subsided, the NHL had ratified a new agreement that established a few key elements which shaped the league for the rest of the decade:

The end of back-diving contracts, as a maximum 50% variance in salaries over the course of the contract ended the practice of embarrassingly low final contract years used to circumvent the salary cap.

The "Roberto Luongo Rule," in which teams that had issued and were paying out those circumventing contracts would be punished through "recapture" penalties.

Contract term limits, as teams could re-sign their own players to a maximum of eight years and sign free agents to a max of seven years.

The ability to retain salary in trades, which significantly changed the transactions market (and the frequency of our visits to independent sites Cap Geek and Cap Friendly).

A 50/50 split in revenue between players and owners that would impact escrow withholdings.

Unlike after the canceled 2004-05 season, the fans returned quickly when the lockout ended. By the end of the decade, revenues continued to climb and the salary cap had gone from $64.3 million in 2013 to $81.5 million by 2019.

What happens next: The NHL and the NHLPA both have a chance to reopen the CBA this September before its 2022 expiration, but there are other options being considered, including an extension on the current deal. Among the sticking points: escrow payments and the future of international play, including an in-season World Cup and Olympic participation.

The league addresses the concussion epidemic

Following his retirement, former NHL enforcer Daniel Carcillo has been a leading voice for player health. AP Photo/Charles Rex Arbogast

What happened: The word "epidemic" was used with some frequency to describe concussions in the NHL, at a time when the sports world as a whole was wising up to the deleterious effects of contact sports on the human brain. From Bob Probert's posthumous diagnosis of CTE in 2010 through the tragic losses of players like Derek Boogaard, Todd Ewen and Steve Montador, it was a decade defined by a growing awareness of concussions and mounting pressure on the NHL -- from legislators and lawyers -- to do something about it.

In March 2011, the league's first big step was a revision to the Protocol for Concussion Evaluation and Management, in which players who were suspected of having suffered a concussion were sent to "the quiet room" for evaluation by a physician. In 2016, that protocol was expanded to include "spotters" in the arena and watching games on television, who could demand a player showing concussion symptoms be pulled from the game for evaluation.

Even with the best intentions, the system was flawed, as players willfully hid symptoms, teams appeared to speed up the evaluation process and players who entered the protocol were later seen as damaged goods. Meanwhile, vocal critics of the NHL, many of whom joined an ill-fated class action suit, demanded help for former players battling health issues as well as increased concussion awareness for today's talents.

What happens next: The NHL and NHLPA will further their partnership on concussion education, as seen in this 2019 video, while linkage between CTE and contact sports -- a link thus far denied by Bettman at every turn, despite its being acknowledged in other sports -- will be further established as more subjects become available for study.

The digital and social media boom

Kings mascot Bailey is among the NHL personalities who have taken to social media with aplomb. Ethan Miller/Getty Images

What happened: NHL teams and players discovered the virtues, absurdities and pitfalls of social media.

Take the Los Angeles Kings and Columbus Blue Jackets, who in the early part of the decade were early adopters of the sassy, humorous tone that other teams would eventually emulate. (Or, in the case of the Golden Knights, amplify to the point of apology.) NHL players would use Twitter to add layers to their personalities (or in some cases, "brand") -- some, like Roberto Luongo and Paul Bissonnette, became as well known for their tweets as their on-ice accomplishments.

But social media wasn't without its drawbacks: Offensive tweets would haunt -- or come back to haunt -- players, with stars like Tyler Seguin claiming they were "hacked" to excuse offensive content.

There are other aspects to the digital and social media boom, including the fact that cameras are everywhere. Whether it's Connor McDavid awkwardly posing for airport photos or Patrick Kane on a college campus bender or Ottawa players trash-talking their coaches in an Uber, images and footage could and would go viral in an instant.

The NHL itself would also leverage social media, first by allowing fans to upload highlights and create GIFs from games, and then by adopting the practice itself. It would also embrace digital media, with a partnership with MLB Advanced Media that transformed the league's video and streaming efforts.

What happens next: New generations of NHL players adopt new forms of social media -- where are you, first rookie TikTok star? -- while teams and the league continue to utilize Twitter, Facebook and YouTube as means through which to offer original (and filtered) content to their customers.

As the next TV rights deal nears for the NHL, expect the league's streaming rights to be a hot property for companies looking to make a sports rights deal splash.

Embrace of the analytics revolution

Both the Hurricanes and Capitals have made significant hires in their analytics departments in recent years. Geoff Burke-USA TODAY Sports

What happened: To understand the expeditious rise of analytics in hockey over the past decade, consider this: A 2012 analytics panel at the MIT Sloan Conference featured noted mathematician Mike Milbury, as well as Brian Burke's infamous line: "Statistics are like a lamppost to a drunk: useful for support, but not for illumination."

Fast forward to 2019, and the NHL's Seattle expansion team was receiving widespread praise for hiring Alexandra Mandrycky as a director of hockey administration, after her three-year stint as an analyst with the Minnesota Wild ended and following her run as co-founder of the War On Ice analytics site. In the same summer, the New Jersey Devils made waves by hiring Tyler Dellow as VP of hockey analytics, a few years after he was a consultant for the Edmonton Oilers. In 2012, he was blogging about them.

Almost every NHL team has a public analytics analyst as of 2019. Toronto Maple Leafs GM Kyle Dubas famously assembled a full department to study them when he was hired. Fancy stats were the calling card of John Chayka when he became the youngest GM in NHL history with the Coyotes. Bloggers who touted possession stats, like Eric Tulsky and Tim Barnes, were snatched up by teams -- the Carolina Hurricanes and Washington Capitals, in Tulsky's and Barnes' cases -- to improve theirs.

Meanwhile, fans and media have become more fluent in analytics, opening up new ways to analyze players or explain the plight of teams. Halfway through the decade, the NHL added possession metrics and other advanced stats to its database.

We've come a long way from the math vs. "eye test" wars.

What happens next: Teams will continue to hire the best and brightest to fill out their front offices with data analysts, and we'll see the first analytics hires climb the ladder to assistant general manager jobs. Meanwhile, the arrival of puck and player tracking will transform the way analytics data is collected and revolutionize the way we evaluate players, especially when it comes to goalies, aka those waiting for their moment in the analytics revolution.

Realignment and the wild cards

It seems unfair that the Bruins and Maple Leafs had to play each other in the first round of the 2019 Stanley Cup playoffs. Jeff Chevrier/Icon Sportswire via Getty Images

What happened: The 2009-10 NHL standings look nothing like the ones a decade later. The Detroit Red Wings and Columbus Blue Jackets were in the Western Conference. There were six divisions, and three of them were named the Southeast, Northeast and Northwest. The top eight teams in each conference made the playoffs.

Then, in 2013-14, a major change: The Wings and Jackets moved East, the league was split into four (sorta) geographically defined divisions and the playoff format shifted to six divisional qualifiers and two wild cards in each conference. How teams qualify for the playoffs would also change, as regulation and overtime wins became a primary tiebreaker, while shootouts' influence on the standings was diminished.

What happens next: Criticism of the current format will continue -- including the "stupidest thing ever" bracketing in the playoffs that frequently forces two of the top teams to face off in the first round -- until it's loud enough to force a change. However, a playoff expansion could also be on the horizon, as the bottom two seeds could end up in "play-in" games/series against the next two seeds.

The dawn of 3-on-3 overtime/expanded video review

Replay review in the NHL has had its ups and downs. Dilip Vishwanat/Getty Images

What happened: In 2015, the NHL's board of governors approved two rules changes that altered the course of the rest of the decade. First, the league dispensed with 4-on-4 overtime in favor of a 3-on-3 format. The thought here was the open ice and back-and-forth nature of the 3-on-3 would produce more overtime goals and reduce the number of shootouts. The results were more kinetic than tedious, and soon the NHL All-Star Game was transformed into a 3-on-3 mini-tournament.

The board also approved a much more controversial innovation: the coach's challenge, which allowed teams to use video review to challenge goals scored on plays that might have been offside or involved goalie interference. The catalyst for the offside reviews was an embarrassing missed call on Colorado Avalanche center Matt Duchene in 2013; by 2019, the reviews were criticized for focusing on players who were "pixels" offside, rather than egregious violations. The reviews of goalie interference were seen as a boon to goaltenders; by 2019, the NHL was still struggling to define what exactly it looked like.

What happens next: The NHL announced in June that rather than reduce the scope of the coach's challenge, it was expanding it to include "missed stoppages in play." That includes hand passes and pucks played after hitting the protective netting, just two of several humiliating missed calls from officials during the 2019 postseason. Referees will also have a chance to check their work on "major and match penalties" and "friendly-fire" high sticks.

Will it end there? Probably not, as the genie has clearly left the bottle and Bettman has said he doesn't see rollback on reviews. As for 3-on-3 overtime, there have been no recent calls to banish it.

Thrashers end; Jets, Golden Knights and Seattle begin

The Thrashers' eventual relocation was driven by many factors, but the team did have some superstars on the roster at times. Scott Cunningham/Getty Images

What happened: The last decade without expansion or relocation in the NHL was the 1950s, and the 2010s kept the streak alive. The Atlanta Thrashers entered the league in 1999 and exited their city in 2011, when True North Sports & Entertainment purchased the struggling franchise to rechristen it as the second coming of the Winnipeg Jets. The Thrashers' legacy would be one of player exoduses and a 12-year existence without a playoff victory, having been swept by the Rangers in their only postseason series.

The Vegas Golden Knights, meanwhile, had the opposite expansion journey: making the Stanley Cup Final in their inaugural season (2017-18) after getting approved as the NHL's 31st franchise. A successful season-ticket drive that left casinos and major corporations out of the pool impressed the NHL board of governors, which awarded Vegas with a team while the Quebec City expansion bid fell short.

In 2019, the NHL accepted its 32nd franchise to the fold, as Seattle was approved by the board of governors to begin play in a renovated KeyArena in the 2021-22 season. Seattle was nearly an NHL city in 2013 had the Coyotes not agreed to a new lease with the city of Glendale. By the end of the decade, Arizona had gone from constant relocation bait to being a cap-ceiling team under new owner Alex Meruelo.

What happens next: All appears quiet on the expansion front after Seattle's entrance to the NHL, but if any current franchises are suddenly on unstable financial and ownership ground, Houston and Quebec are ready and waiting for a relocation.

Legalized sports wagering

The NHL has partnered with MGM Resorts International in a marketing deal, and to provide data for use in betting. AP Photo/Seth Wenig

What happened: It began when the Golden Knights entered the NHL. Betting on hockey at neighboring casinos by local and visiting hockey fans became part of the game-night experience. Vegas sportsbooks reported a previously unheard-of spike in hockey wagering, for a sport that had previously failed to inspire much action.

Then things got really interesting: In May 2018, the U.S. Supreme Court ruled that the Professional and Amateur Sports Protection Act was unconstitutional, opening up legalized sports wagering to all 50 states. Now, instead of the wink-wink betting of daily fantasy sports that the NHL had invested in, wagering on NHL games could become commonplace. Bettman, previously an opponent of legalized sports wagering on hockey, embraced it as a new avenue through which hockey could attract fans.

What happens next: Suffice it to say, the rollout of sports wagering has been methodical. Just 13 states including Nevada, as well as the District of Columbia, have legalized it, although dozens more are expected to do so in the near future.

The NHL, meanwhile, has been cutting licensing deals with sportsbooks; when all that player tracking data starts flowing in, get ready to wager on everything from location of shots to the speed of skaters.