(CNN) -- The teenage birth rate in the United States has fallen to a record low in the seven decades since such statistics were last collected.
A report released Tuesday by the National Center for Health Statistics showed the teenage birth rate for American teenagers fell nine percent from 2009 to 2010. The national level, 34.3 teenage births per 1,000 women between the ages of 15-19, is the lowest since 1946.
The rates dropped across all racial and ethnic groups, and nearly all states. Experts suggested that the numbers may mean more teens are delaying sex or using contraception, representing gains for both abstinence-only and contraceptive education programs.
Teenage pregnancy is linked with several health and social issues such as poverty, out-of-wedlock births and education, as well as developmental issues, welfare and physical and mental health issues for the child.
"This nation has made truly extraordinary progress in reducing both rates of teen pregnancies and teen births," said Bill Albert, the chief program officer for The National Campaign to Prevent Teen and Unplanned Pregnancy. "It is not a stretch to say that this is one of the nation's great success stories of the past decades."
Babies born to teens between 15 to 19 numbered 367,752 in 2010, compared with 409,802 in 2009.
Birth rates peaked most recently in 1991. The teen birth rate that year was 61.8 live births for each 1,000 women. Had that rate persisted, there would have been about 3.4 million additional births to teenagers from 1992 to 2010.
The data from the report, which was derived from birth certificates, doesn't pinpoint why the teenage birth rate has decreased over the last few decades, said Brody Hamilton, an author of the report and a statistician at the Centers for Disease Control and Prevention.
"With teens, there are a lot of factors," he said. "The economy is cited for overall downturn in the number of births. With teens, there are public policy programs directly addressing this teen pregnancy issue. It's a mixture of things involved. We cannot tease that out with the data set that we have."
A report released last year found that the rate of teenagers having sex decreased slightly, following an overall trend of decline in teenage sex in the last 20 years. Recent data has found increased use of contraception, such as condoms and hormonal birth control.
"These trends may have contributed to the recent birth rate declines," wrote Hamilton and a co-author.
The short answer is that teens appear to be delaying sex or using contraception.
Despite the gains in teen pregnancy prevention, the U.S. still lags behind other industrialized countries. For example, Lithuania (17 per 1,000), Poland (16) and Canada (14) have lower teen pregnancy births than the United States, according to the UN Demographic Yearbook.
"It's still the case that the U.S. is an outlier when it comes to teen pregnancy," Albert said.
The teen birth rates also vary widely by race in the United States. Hispanics have the highest teenage birth rates at 55.7 births per 1,000, and black teenagers have the second highest with 51.5. Asians have the lowest teenage birth rate with 10.9.
Movies and TV shows about teen pregnancy, such as MTV's "Teen Mom" and "16 and Pregnant" has spread awareness about the issue, Albert said. A national survey of teenagers asked whether the shows glamorized teen pregnancies and the majority reported that it had the opposite effect.
And over the years, controversy has ensued between those who advocate abstinence-only programs and supporters who want more contraception education.
"Over the past decade in particular, there has been a growing number of sex education programs that have been carefully evaluated and have shown it can change teen behavior, get them to delay sex or use contraceptives." Albert said.
The lower teenage birth rate is a duel victory for both sides, he said, because sex education varies so much from one community to another.
"It's a combination of less sex and more contraception. Both sides should declare victory," Albert said. "I would resist the temptation for a magic bullet to explain the declines in teen pregnancies. I suspect it's a rich brew of reasons why the rates are going down."