U.S. electric vehicle sales may be finally seeing the hockey stick growth market watchers have been waiting for.

The 2018 numbers are in, and total U.S. EV sales came in at 361,307 for the year — up 81 percent over 2017 — according to the tracking website Inside EVs.

For Chris Nelder, manager of Rocky Mountain Institute’s mobility practice, the results came as a surprise.

“I did not expect the growth rate to be over 30 percent" for 2018, he said. “I expected it to be in the 20 percent range, which is where it’s been.”

“I did expect we’d have a sharp increase in the rate adoption sometime soon," he added. “But I didn’t think it would be in 2018.”

Source: Inside EVs

Last year’s strong sales performance really came down to one thing: Tesla. The Silicon Valley automaker sold 139,782 units of the Model 3 in 2018, according to Inside EVs. Including the Model S and the Model X, Tesla was responsible for more than 50 percent of total plug-in vehicle sales last year.

The Toyota Prius Prime was the second-bestselling EV of 2018, with 27,595 units sold. GM’s Model 3 challenger, the Chevy Bolt, made the top 10 list but was well behind the market leader, with just 18,019 sales for the year.

Source: Inside EVs

U.S. EV sales to date have been underwhelming. While launching an entirely new class of vehicles is no easy feat, China has seen adoption levels surge, while European countries lead on a per-capita basis.

The U.S. EV sector has seen incremental growth over the past several years, but it has yet to reach an inflection point. And sales actually saw a dip in 2015.

Source: InsideEVs

In 2017, U.S. EV sales totaled 199,818 — up 26 percent over 2016. That number set a new record for the U.S. market, although plug-in sales barely surpassed 1 percent of total market share.

Historic EV sales growth in the U.S. has been steady, but it’s safe to say it hasn’t spiked. 2018 may prove to be the year that changed, but it will depend in large part on how well automakers other than Tesla perform.

Taking the Model 3 out of the mix, U.S. EV sales increased by only 11 percent last year, a poor showing by most standards.

But Nelder notes that many automakers were focused on introducing new EV models and retooling their production lines in 2018. While this didn't translate to enormous sales, he believes these investments will start to pay off in the coming months.

“I think it’s going to be a whole different game,” he said. “I don’t think 2019 is going to be all about the Model 3. There are a lot more manufacturers making a lot more EVs.”

There are several new mass-market EVs available with over 200 miles of electric range, such as the Kia Soul and Kia Niro. At the same time, brands such as Mercedes, BMW, Porsche, Jaguar and Audi are launching headline-grabbing high-performance electric cars — and putting real pressure on Tesla for the first time.

“In 2019, we’re going to have much more significant participation from other major manufacturers, especially in the high-end luxury crossover/SUV segment,” said Nelder. “And it’s there that I think people are going to get excited about what’s happening. That’s not the consumer model stuff that we all need and want to see, but it is the sexy stuff. It is the stuff that generates headlines and gets people to go into showrooms and gets real money to flow.”