It has long been known the U.S., and California in particular, have been driving forces behind the demand for Tesla Model S and Model X vehicles.

What has never been clear is exactly how much of the automaker’s sales come from its home market. Tesla’s policy has been, and still remains, that it doesn’t break down sales by market.

But a new report by Moody’s gives us a glimpse into just how important the U.S. is to Tesla. Moody’s, citing company reports and registration data from Polk, says Tesla dominates the EV market in the U.S., selling 45 percent of all electric vehicles in the first half of this year.

That is well ahead of General Motors, which had 16 percent of the domestic market thanks to its Chevy Bolt.

While Moody’s does not give specific sales numbers for each electric model sold in the U.S., there are other ways to track those numbers.

The research firm Autodata reports monthly U.S. vehicle sales for each model, except Tesla.

Since Autodata reports GM sold 7,598 Chevy Bolt cars and Moody’s says the Bolt made up 16 percent of all EV sales, here’s a snapshot of electric vehicles in the U.S., including Tesla’s two models:

• Overall, Americans bought about 48,000 pure electric vehicles. That is roughly one-half of 1 percent of the 8.45 million autos sold between January and June of this year.

• Tesla’s Model S had 29 percent of the market, according to Moody’s. That means Americans bought about 13,900 Model S cars in the first half of 2017.

• Tesla’s Model X and the Chevy Bolt each had 16 percent of the U.S. EV market, which works out to roughly 7,600 for each model.

• The Nissan Leaf had 15 percent of the market, according to Moody’s. Which matches the total of 7,248 Leaf cars sold, according to Autodata.

So what do all these numbers tell us?

First, electric vehicle sales still make up just a tiny portion of total U.S. auto sales. For all the talk about America going green, the numbers show electric vehicles have a long way to go.

Second, the U.S. remains crucial to the health of the Tesla Model S. In fact, 55 percent of the 25,450 Model S vehicles delivered in the first half of the year went to customers in the U.S. Of the 21,500 Model X SUVs delivered between January and June, about 36 percent went to U.S. buyers.

Tesla’s dependence on the U.S. is not a surprise since it is based in California and the Golden State is filled with Tesla loyalists. In the future, as Tesla expands sales in China that market will take on greater importance and a greater percentage of vehicle deliveries.