The U.S. supply of emergency oil has hit its lowest level since 1983, according to newly released federal data. The U.S. Strategic Petroleum Reserve (SPR) is down to 340.3 million barrels, according to the data released on Monday. The last time that levels were this low was 1983, when the Reagan administration was filling up the reserve for the first time. The U.S. established the emergency oil reserve in 1975 after an oil producer embargo against the country triggered an energy crisis.