California has become the first U.S. state to register more than a million plug-in cars, with almost one-quarter of them arriving in 2021 alone, as electric vehicle sales finally accelerate after years of slow growth.

In California’s case, reaching the 1-million milestone took 11 years.

As of Dec. 31, California drivers had registered 663,014 purely electric cars and 379,125 plug-in hybrids, which use gasoline when not running on electricity. Of those, 183,933 battery-electric cars and 63,141 plug-in hybrids were bought or leased in 2021, according to data from the California Energy Commission. Together, they accounted for more than 12% of all light-duty vehicles sold in the state last year.

Electric vehicle sales in several key markets around the world are now showing rapid growth, as the number of available models expands and consumers become comfortable with the technology. BloombergNEF estimates that the inflection point where EV sales take off can happen once they represent at least 10% of new car sales, with China and Europe already passing that mark.