The 1960's witnessed considerable change in educational attainment levels. Of Americans 25 years old and over in 1970, 52 percent were at least high school graduates, as compared with 41 percent in 1960 and 34 percent in 1950. There was considerable variation in educational attainment levels in 1970 among the various age groups in the population. For example, among older Americans 75 years old and over only 21 percent were high school graduates, but among the younger adults, those 20 to 24 years old, who would have recently completed their high school education, 78 percent were high school graduates. At each preceding younger age from 75 years old and over down to 20 to 24 years, the median number of years of school completed rises. Among those 50 to 54 years old, the median was 12.0 for the men and 12.1 for the women. The median reached a high of 12.7 for the men 20 to 24 years old and 12.6 years for the women of this age. Negroes and persons of Spanish heritage lagged behind the total population in educational attainment, but they are making considerable gains. In 1970, 31 percent of Negroes 25 years old and over had graduated from high school; however, among the younger Negroes, 20 to 24 years old, 62 percent were high school graduates. Among persons of Spanish heritage, 36 percent of those 25 years old and over were high school graduates as compared with 58 percent of those 20 to 24 years old. (Author/JM)