(CBS NEWS) -- When it comes to sex, teens may be more responsible than they're often given credit for.

According to new government data, the percentage of American teens having sex is lower than in decades past – and more teens who do have sex are now using contraception.

The report, published by the CDC's National Center for Health Statistics, finds an estimated 55 percent of U.S. teens have had sex at least once by the time they turn 18.

Among adolescent females aged 15 to 19, 42 percent report having sex at least once. For males, that number was 44 percent. The numbers have gradually dropped since 1988, when 51 percent of female and 60 percent of male teens reported having had sex.

For the study, the researchers interviewed more than 4,100 male and female teens aged 15 to 19 from across the U.S. from 2011 through 2015.

The data showed that virtually all of the sexually-experienced female teens (99.4 percent) had at some point used a method of contraception, up from 97.7 percent in 2002.

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