Teen pregnancies fell to the lowest recorded levels in the U.S., according to a federal report issued Thursday.

Teen pregnancies fell 9 percent in 2010, the largest decline since a year after the end of the Second World War, according to the report released Thursday.

Since 1991, teen pregnancy rates fell 44 percent, according to data collected by the Centers for Disease Control and Prevention that started tracking pregnancies nearly 70 years ago.

I am aware of no other social problem that has improved so dramatically over so many years, Sarah Brown, CEO of The National Campaign to Prevent Teen and Unplanned Pregnancy, said in a statement. Progress in reducing teen pregnancy has been nothing short of remarkable.

Brown attributed the decline of teen pregnancy with a magic formula of greater awareness and better access to contraception.

Teens are being more careful for a number of reasons, including the recession, more media attention to this issue--including the '16 and Pregnant/Teen Mom effect'--and more attention to and investment in evidence-based programs. But at the end of the day, the thanks and admiration go to teens themselves, Brown said.