A new study done by the U.S. Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics has given insight into the sex lives of modern American teenagers. The study found if they have had sex, how often they use contraceptives and the rate of teenage pregnancy. These stats were then compared to past findings to show what direction the numbers are headed.

How many teenagers have had sex by age 18?

The study from the CDC found that around 55 percent of teenagers have had sex at least one time when they turn 18. For adolescent males between the age of 15 to 19, 44 percent of them reported having sex at least once. Among adolescent female in the same age range that number was 42 percent.

These numbers have reduced drastically since 1988, when they were 60 percent for males and 51 percent for females. For their study the CDC interviewed over 4,100 teenagers between the ages of 15 to 19 from 2011 to 2015.

Contraceptives and teenage pregnancy

The CDC study found that due to the increased use of contraceptives, the pregnancy rate and birth rate among teenagers continued to decline for the 25th consecutive year. This goes hand-in-hand with a study earlier this year from the CDC that shows that teen birth rate in America was at a historic low of just 24 births per 1,000 women. For comparison, in 1991 this number was 61 births per 1,000 women.

Data from the study showed that 99.4 percent of sexually experience teenage females had used a method of contraception at some point, up from 97.7 percent in 2002.

Teenage females also report that 81 percent of them used birth control the first time they had sex and 90 percent used it during their last sexual encounter within the last three months. Condoms are the most common contraceptive, with 90 percent of teenage girls reporting that they used them. The next two highest forms were withdrawal (60%) and oral contraceptive pills (56%).

Who are teenagers having sex with?

The report also found that few teenagers, seven percent of males and two percent of females, had their first sexual experience with someone they "just met." In contrast, the majority of males (51%) and females (74%) said that their first sexual experience was with someone that they were "going steady" with. Lastly, 20 percent of females and close to 40 percent of males said their first experience was with someone who they thought of as "just friends."