From: Teaching evolution in U.S. public middle schools: results of the first national survey
 | Not covered | 1–2 | 3–5 | 6–10 | 11–15 | 15–20 | 20 or more class hours | Total | N |
---|---|---|---|---|---|---|---|---|---|
 | % | % | % | % | % | % | % | % |  |
Class hours devoted to general evolutionary processes | |||||||||
 Middle school | 39.2 | 13.9 | 16.0 | 13.0 | 6.2 | 6.6 | 5.1 | 100.0 | 641 |
 High school | 9.3 | 8.1 | 13.5 | 24.8 | 17.4 | 14.2 | 12.7 | 100.0 | 787 |
Class hours devoted to human evolution | Â | ||||||||
 Middle school | 55.1 | 16.3 | 14.5 | 6.1 | 2.1 | 4.3 | 1.5 | 100.0 | 646 |
 High school | 21.8 | 27.4 | 20.4 | 14.0 | 7.3 | 4.6 | 4.5 | 100.0 | 785 |