The average public high-school graduation rate has remained relatively flat

The average graduation rate of public high-school freshmen - an estimate of on-time graduating - decreased slightly in the 1970s and since that time has remained between 70 and 76 percent.

Average public high-school freshman graduation rate

The average public high-school graduation rate has remained relatively flat

Source: U.S. Department of Education, Digest of Education Statistics, 2010.