The U.S. Census Bureau has released 2017 data on Educational Attainment of the: Population 18 Years and Over, by Age, Sex, Race, and Hispanic Origin; Population 25 Years and Over, by Selected Characteristics; and Detailed Years of School Completed by People 25 Years and Over by Sex, Age Groups, Race and Hispanic Origin. For the first time in U.S. history, 90% of the population age 25 and older has completed high school.
Data can be obtained at https://www.census.gov/data/tables/2017/demo/education-attainment/cps-detailed-tables.html.