In the survey made by United States
in the year 2009, by age 20, the percentage of youth in US that are engaged in
sexual intercourse is 77%. The percentages in the national level are as follows,
for the twelfth -graders are 49%, 40% of eleventh- graders, 29% of
tenth-graders and for the 9th graders, 21% are sexually active.
These are all according to Eaton and others, 2010.
