Household Income Trajectory Groups for Adults in the Alameda County Study, Alameda County, CA, 1965–1994. Consistently low: 16.35% (n=440), mean age = 67 years, range= 47–102 years, mean 1965–1994 income = $14751; Moderately low: 66.03%% (n=1777), mean age = 64 years, range= 46–97 years, mean 1965–1994 income = $29572; Increasing: 11.04% (n=297), mean age = 57 years, range= 47–86 years, mean 1965–1994 income = $66258; High: 6.58% (n=177), mean age = 71 years, range= 49–91 years, mean 1965–1994 income = $78403.