The San Francisco metro area has reached a major milestone in the adoption of electrified vehicles. The area has become the first in America where electric and hybrid vehicles make up more than 50 percent of new vehicle sales.

The San Francisco “Designated Market Area” (DMA) achieved the landmark sales figure in March. The success of electrified vehicles appears to be sustained, too, because sales of electrified vehicles were even higher in April, at 53.1 percent, new research from S&P Global finds.

The organization suggests that there are two major reasons for the success of electrified vehicles in the area. First, the city’s demographic makeup is remarkably similar to that of buyers of electrified vehicles.

Indeed, San Francisco buyers tend to be younger than those in other areas, and they tend to be more affluent, too. For instance, 46 percent of the city’s residents have a household income of more than $200,000, while 40 percent of EV buyers nationwide have the same.

Read: Hybrids Remain The Preferred Electrified Choice For U.S Car Shoppers

 San Francisco Becomes First U.S. City Where Electrified Cars Make Up 50% Of Sales

The concentration of buyers of electrified vehicles in the metro area isn’t limited to what is generally considered the city of San Francisco. Nearby enclaves like Los Altos, Saratoga, Piedmont, and others are big buyers of the vehicles, S&P Global notes. Intriguingly, San Ramon, where Chevron’s global headquarters is located, has the highest penetration of EVs in the DMA.

While hybrid vehicles are a major contributor to the success of electrified vehicles in the area, purely electric vehicles are more successful there than in the rest of America. In March, EVs made up 34.3 percent of sales there, more than four times the national average.

Unsurprisingly, Tesla’s vehicles are highly popular in the region. Nearly one in four new vehicles sales in the San Francisco DMA, regardless of powertrain, were manufactured by the company that owes much of its success to California.

Tesla wasn’t the only automaker with big success in the area, though. For instance, sales of the VW ID.4 were proportionally four times stronger there than in the rest of the country in March.

The success of electrified vehicles in San Francisco is undoubtedly a positive sign for the technology, but does point to the fact that EVs are still mostly bought by the affluent. While the rising competition and tax incentives may help promote more affordable vehicles, that is likely to remain a hurdle for the rest of the U.S. in the near future.

 San Francisco Becomes First U.S. City Where Electrified Cars Make Up 50% Of Sales