1948: Only 33 percent of all adults in the United States graduated from high school.

1963: The high school graduation rate increases to 46 percent.

Today: Eighty percent of U.S. adults hold high-school diplomas.

1929: Pop Warner Little Scholars, a national youth football program, is founded in Philadelphia, Pennsylvania.

1947: Pop Warner hosts its first National Championship event.

1998: Pop Warner has leagues in 38 U.S. states.

Today: Pop Warner is in 1,400 communities nationwide; the NFL Players' Association estimates that 60 to 79 percent of NFL players took part in Pop Warner football.

1970s-1990s: Total participation in high-school football hovers around one million.

Today: Football remains the largest male-participant, high-school sport in the United States.