Oil production in the Middle East dropped by over a quarter in March, as the Iran war continues to destabilize the world’s energy supply. 

OPEC’s production plunged 27%, from 28.7 million barrels per day to 20.8 million, according to data released by the organization on Monday. The nosedive was driven by losses in Iraq, Saudi Arabia, the United Arab Emirates, and Kuwait, and it marks the steepest drop since the 1980s, according to Bloomberg.