Since crude prices cratered, no oil-producing country has eliminated as much production as the U.S.

After OPEC's November 2014 decision to let the market set prices, the price of oil declined, yet U.S. oil production continued to gain temporarily, topping out at 9.6 million barrels a day in April. But since then, U.S. output has fallen by about a half million barrels a day, dipping to 9.1 million barrels a day in the latest weekly government figures. More declines are expected.