She said, "Many kids don't realize that each 20-ounce bottle averages 15 to 20 teaspoons of sugar. That's a lot of extra calories they don't need." Teens are also less likely to be sexually active -- defined as having sexual intercourse during the past three months. In 2015, 30 percent of teens said they were sexually active. In 1991, that figure was 38 percent of teens, according to the report.