zlacker

A 50% graduation rate for US secondary education had been attained by the 1947-48 school year, which is now 75 years ago. By 50 years ago (1972-73), the actual rate was 75%, among 17 year olds. (Note that some normal-schedule students would be graduating at age 18, and other statistics look at graduation or G.E.D. equivalent at later ages, e.g., 19 or 20.)

That said, yes, there was a dramatic increase in attendance and graduation from ~1900, when the graduation rate was about 6%.

US Department of Education, 120 Years of American Education: A Statistical Portrait, p 55, "Table 18 --- High school graduates, by sex and control of institution: 1869--70 to 1991--92"

<https://books.googleusercontent.com/books/content?req=AKW5Qa...> (PDF)