Zlatan Ibrahimovic’s 50th game in Major League Soccer came earlier this month. The LA Galaxy suffered a soul-crushing 4-3 defeat to the Seattle Sounders, conceding in the 89th minute, but not before their Swedish frontman had contributed a goal and an assist, bringing his tally in his first 50 league appearances to 55 combined goals and assists.

Ordinarily, this would be an unprecedented achievement, but Ibrahimovic’s productivity had already been all but matched by Josef Martinez and Carlos Vela who both managed 54 combined goals and assists in their first 50 MLS games. These are three very different players playing for three different teams, but as a trio they are setting a new standard.

Indeed, Ibrahimovic, Martinez and Vela have become the billboard boys of MLS over the past two years. Their sparkle helps sell tickets and shift jerseys, but what is revealed if we scratch beneath the surface of their recent achievements? Is it now easier to score in MLS than it has been previously? Has that been a factor in their success?

Recent seasons has seen the average number of goals in an MLS match creep up and up. Last season saw 3.19 goals scored per regular season game, up from 2.97 the season before that and 2.81 the season before that. In fact, not since the 2002 season had the average goals per regular season game ratio tipped the scales at three until last season. This season is currently charting at 3.1 goals per game.

Of course, MLS has been home to clinical goalscorers before. Roy Lassiter’s single season record of 27 goals stood for 16 years until Chris Wondolowski equalled it during the 2012 season for the San Jose Earthquakes. Stern John also scored 26 goals over the 1998 season for the Columbus Crew while Mamadou Diallo reached the same number for the Tampa Bay Mutiny in 2000.

But of the five most prolific goalscoring seasons in MLS history, four have come in the last seven years. As things stand, it’s likely that Vela will set a new single season scoring record just 12 months after Martinez pushed the record up to 31 goals in the 2018 campaign. The Los Angeles FC forward is just five goals away from pushing it up again.

Vela has never before charted such impressive numbers. The Mexican, who is a forward, but hardly a six-yard box poacher, enjoyed a successful five-year stint at Real Sociedad, but he never bettered a ratio of a goal every three games. For context, Vela currently has 27 goals in 26 league games for LAFC this season - better than a goal every game.

Carlos Vela is on course to break MLS’s goalscoring record. Photograph: Marcio José Sánchez/AP

Those looking to use the current level of MLS goalscoring to make a judgement against the league as a whole might point to Vela’s dramatic upturn in numbers as evidence of its defensive frailty. Similarly, Martinez’s goalscoring ratio was less than impressive during his time in Europe – he only scored seven times in three years for Torino.

Ibrahimovic’s success has been less surprising given his magnificent achievements in the sport before pitching up at the LA Galaxy last summer. Indeed, his MLS scoring rate (0.9 goals per game) is pretty much on par with the numbers he charted at Milan (0.875 goals per game) and Paris Saint-Germain (0.92 goals per game). At 37, though, a drop-off might have been expected.

One explanation for the surge in MLS’s goals per game could be the number of expansion teams that have entered the league in recent years. FC Cincinnati, for instance, have conceded 72 times in just 29 games so far this season. They are just two goals away from tying Orlando City’s record for MLS’s worst defensive season. Two seasons before that, Minnesota United conceded 70 times in their first top flight season.

Historically, there is a direct correlation between expansion seasons and a rise in goalscoring. In 1998, for instance, the Chicago Fire and the Miami Fusion joined the league and the average goals per game shot up from 3.26 the season before to 3.65 - a record that still stands to this day. In fact, the early days of MLS were characterised by goals and lots of them. Only once in the league’s first seven seasons did the goals per game ratio drop below three (1999 - 2.86 goals per game). At that stage of MLS’s development, every team was essentially an expansion side.

MLS’s salary cap and Designated Player rule means teams naturally weight their payroll towards attackers. They are after all the ones who catch the eye most of all, the most obvious of difference makers.

Raising the salary cap or lifting the number of DPs permitted would surely see MLS teams achieve a greater balance across their rosters, potentially improving the standard of the league’s defensive play. Until then, however, the top-heavy nature of most MLS sides will keep the goalscoring rates high. With Inter Miami, Nashville, Austin FC and a St Louis team set to join the league over the next three years, they could get even higher. History suggests this is probable.

It may well be easier to score in MLS now than it was a few years ago. Whether that is the product of an increase in attacking potency or a decrease in defensive quality is largely down to interpretation, but if goals are the currency of the sport then MLS is particularly rich right now.