The U.S. likely holds more recoverable oil reserves than both Saudi Arabia and Russia, a startling change for a country once so concerned about energy it had banned most exports of crude oil.

The U.S. has more than 50% of remaining oil reserves tucked into unconventional shale oil, where profitability varies, but where cost cutting and efficiencies have gradually lowered breakeven points.

Texas alone holds more than 60 billion barrels (Bbbl) of shale oil, according to new data from an independent estimate of world oil reserves, which was released by Rystad Energy. Rystad is an independent oil and gas consulting service and business intelligence data firm headquartered in Oslo, Norway.

Rystad’s analysis distinguishes between reserves in existing fields, reserves in new projects, and potential reserves in recent discoveries as well as in yet-undiscovered fields, according to Per Magnus Nysveen, senior partner and head of analysis for the firm.

The firm used an established standard approach for estimating reserves for all fields in all countries to make comparable reserve comparisons across the world for OPEC and non-OPEC countries.

Other public sources of global oil reserves, like the BP Statistical Review of World Energy, are based on official reporting from national authorities, reporting reserves based on a diverse and opaque set of standards.

In its 2016 report, BP Plc’s (NYSE: BP) showed the U.S. as a significant player in crude reserves, but not in the same category with other nations.

OPEC countries, such as Venezuela, report official reserves apparently including yet-undiscovered oil, while others like China and Brazil officially report conservative estimates and only for existing fields.

Rystad Energy now estimates total global oil reserves at 2,092 Bbbl, or 70x the current production rate of about 30 Bbbl per year.

By comparison, the cumulative amount of oil produced up to 2015 amounts to 1,300 Bbbl.

Unconventional oil recovery accounts for 30% of the global recoverable oil reserves, while offshore accounts for 33% of the total. The seven major oil companies hold less than 10% of the total.

Rystad’s data confirms that there is a relatively limited amount of recoverable oil left on the planet.

“With the global car-park possibly doubling from 1 billion to 2 billion cars over the next 30 years, it becomes very clear that oil alone cannot satisfy the growing need for individual transport,” the report said.

Darren Barbee can be reached at dbarbee@hartenergy.com