The U.S. teen birth rate in 2009 fell to its lowest point in 70 years of record-keeping — a decline that stunned experts who believe it's partly due to the recession.

The birth rate for teenagers fell to 39 births per 1,000 girls ages 15-19, according to a government report released Tuesday. It was a 6 percent decline from the previous year and the lowest since health officials started tracking the rate in 1940.