 During the 1970s, the presidential administrations of Echeverría (1970–76) and López Portillo (1976–82), tried to include social development in their policies, an effort that entailed more public spending.With the discovery of vast oil fields in a time in which oil prices were surging and international interest rates were low -and even negative- the government decided to borrow from international capital markets to invest in the state-owned oil company, which in turn seemed to provide a long-run income source to promote social welfare.This method produced a remarkable growth in public expenditure, and president López Portillo announced that the time had come to "manage prosperity" as Mexico multiplied its oil production to become the world's fourth-largest exporter.