Mortgage underwriting standards declined precipitously during the boom period. The agricultural sector declined precipitously in the 1980s. The military buildup spurred economic growth, and unemployment fell precipitously. Eastern populations have declined as well, though not as precipitously. Sixteen years later, world coffee demand plunged even more precipitously with the Great Depression. Meanwhile, the Amerindian population began to decline precipitously, dying from diseases brought by the Europeans. This highpoint was followed by a precipitously decline in numbers. At the same time mining costs had risen precipitously. The value of Iran's currency declined precipitously after the revolution. The plane suddenly shook and its airspeed dropped precipitously. Presley's condition declined precipitously in September. The United States population peaked in 1968, but fell precipitously in the 1970's. Sales of records declined precipitously during the Great Depression of the 1930s. From around 1951, Young's level of playing declined more precipitously as his drinking increased. The Yazidi community of Turkey declined precipitously during the 20th century.