CDC: 40% of U.S. teens are sexually active

May 5 (UPI) -- The percentage of teens in the United States that are sexually active has continued a 30 year decline, the Centers for Disease Control and Prevention reported Wednesday.

Roughly 40 percent of never-married teens between 15 and 19 years of age reported having sexual intercourse in 2017, the most recent year for which data is available, and an overwhelming majority uses contraception -- condoms, for the most part -- the agency said in the new report.

The declining rate of sexually active teens continues a trend that started in 1988, and parallels declines in both teen birth and pregnancy rates seen in the country since then, according to the CDC.

"Understanding these patterns and trends in sexual activity and contraceptive use can help provide context for the declines that have been seen in the U.S. birth and pregnancy rates for teenagers since the early 1990s," researchers wrote in the report.

From 2015 through 2017, 42 percent of never-married female teenagers and 38 percent of never-married male teenagers reported having had sexual intercourse, the CDC's National Center for Health Statistics noted. Both of these numbers dropped significantly from 2002, when they were each 46 percent.

Among all females between 15 and 24 years of age included in the analysis, which was based on participants in the National Survey of Family Growth, 21 percent said they had had sexual intercourse by age 15. By age 17, this figure increased to 53 percent, while it was 79 percent by age 20.

Among all males between 15 and 24 years of age, 20 percent indicated that they had had sexual intercourse by age 15. As with their female peers, by age 17, this increased to 48 percent and again to 77 percent by age 20.

Nearly 80 percent of females and nearly 90 percent of males between 15 and 24 years of age who said they had sexual intercourse before age 20 reported that they used contraception the first time.

A higher percentage of females who had sexual intercourse the first time at 15 to 16 years of age, 79 percent, and at 17 to 19 years of age, 83 percent, said they used a method of contraception their first time -- compared with those who were 14 years of age and younger, at 57 percent.

Similarly, a higher percentage of males who had sexual intercourse for the first time at 15 to 16 years of age, at 93 percent, and at 17 to 19 years of age, at 91 percent, reported using a method of contraception the first time they had sex, compared to those who were 14 years of age and younger, 78 percent.

In 2015 to 2017, 97 percent of female teenagers who had ever had sex reported using condoms, and 19 percent reported a history of "emergency contraception."

In addition, 20 percent of female teenagers who were sexually active indicated that they had used long-acting reversible contraception, which includes an intrauterine device, or IUD, and implant contraceptives.

"The condom remains the most commonly used contraceptive method among female teenagers," the report noted.