A growing number of electric vehicle owners are making the switch back to gas-powered engines, according to new data compiled by Mobility Global.

Historically, EV owners have been loyal to the electrified market, but by June of this year over 52,000 previously fully electric-car buyers switched to gasoline vehicles, a 16% year-over-year jump.

The EV loyalty that remains is largely driven by Tesla owners/ According to Mobility Global, 71% of Tesla owners said they would buy another EV, which is higher than the 37% of non-Tesla owners who said they would stick with an EV. Of non-Tesla owners, 44% transitioned from EVs to gasoline vehicles. And 18% switched from fully electric to hybrid.

The automotive data provider said that product availability is a big driver of the defection.

“A household may prefer a hybrid but find few choices in its desired segment, body style, price range or brand,” the company said.

That could lead brand-loyal shoppers to make an important decision: stick with their preferred brands and switch powertrains or switch brands to get the powertrain they really want.

The lack of variety in electrified options isn’t a surprise as many automakers have scaled back their EV production to meet the demands of the U.S. market. And with Chinese EV automakers like BYD largely not allowed in the states, options are limited in comparison to other countries.