Orlando, Fla. ? The number of teenagers having babies has declined sharply in the past several years nationally, recently released statistics show.

The national birth rate for 15- to 19-year-olds reached its lowest level in more than a decade in 2005, according to a report from the Federal Interagency Forum on Child and Family Statistics released last month.

Experts say less support of teen childbirth in society and increased awareness of the risks of unprotected sex have encouraged teens to wait longer to have sex and to use contraception when they do decide to start.

“The good news is that teenagers are learning,” said David Landry, senior research associate for the Guttmacher Institute, an independent nonprofit organization that focuses on reproductive health. “One, they’re having sex at a later age … and two, they’re more likely to use contraception when they do have sex.”

From 1995 to 2002, 23 percent of the decline in teen birth rates for 15- to 17-year-olds was because of delays in sexual activity, according to a 2006 report from Columbia University and the Guttmacher Institute. Increased and improved contraception use accounted for 86 percent of the decline among 15- to 19-year-olds, the report said.

The study analyzed data from the National Survey of Family Growth from the Centers for Disease Control and Prevention.

A variety of contraceptive methods and an increase in campaigns to prevent teen pregnancy are two reasons adolescents may be paying more attention, Landry said.

“Many of those methods didn’t even exist 10 years ago,” Landry said.