The share of total family living expenses devoted to food dropped from 35% in 1970 to 27% in 1986, while net household savings, which averaged slightly over 20% in the mid-1970s, averaged between 15 and 20% in the 1980s. Japanese households thus had greater disposable income to pay for improved housing and other consumer items. The increase in disposable income partly explained the economic boom of the 1980s, which was pushed by explosive domestic demand, as well as a sharp rise in the value of the yen after the Plaza Accord.