US surplus production capacity had declined from 4 million bpd to around 1 million bpd between 1963 and 1970, increasing American dependence on foreign oil imports. When Richard Nixon became president in 1969, he assigned George Shultz to head a committee to review the Eisenhower-era quota program. Shultz's committee recommended that the quotas be abolished and replaced with tariffs but Nixon decided to keep the quotas due to vigorous political opposition. Nixon imposed a price ceiling on oil in 1971 as demand for oil was increasing and production was declining, which increased dependence on foreign oil imports as consumption was bolstered by low prices. In 1973, Nixon announced the end of the quota system. Between 1970 and 1973 US imports of crude oil had nearly doubled, reaching 6.2 million barrels per day in 1973. Until 1973, an abundance of oil supply had kept the market price of oil lower than the posted price.