The number of new teenage mothers in the United States is at its lowest level in nearly 70 years but remains the highest of any major developed country, according to official figures released Tuesday.

The current rate of 34.3 births per 1,000 women aged 15-19 is down 44 percent from a peak in 1991, and is 64 percent lower than the record set during the 1957 "baby boom" of 96.3 births per 1,000.

In 2010 just under 368,000 babies were born to women aged 15-19, in addition to 4,500 born to girls aged 10-14, according to the figures released by the National Center for Health Statistics.

In one year, between 2009 and 2010, the rate plunged by nine percent, a "phenomenal" decline, Brady Hamilton, an author of the study, told AFP.

He attributed the "good news" of the report to both the general decline in fertility among all age groups -- except women aged 40-45 -- and to "numerous programs" aimed at preventing teen pregnancy.

However, the US teen birth rate remains far higher than that of other industrialized countries.

A UN report from 2009 found a rate of 16.5 births per 1,000 teenage women in Australia, 12.2 in Spain, 10.2 in France, 9.8 in Germany, 4.9 in Japan and 25 in Britain.

The US report said the teen birth rate was down across all racial groups and all areas of the country.

However, the rate varies by region, with the southern state of Mississippi recording a rate of 55 births per 1,000 teenage women and the northeastern state of New Hampshire recording just 15.7.

The overall teen birth rate "continues to be a matter of public concern because of the elevated health risk for teen mothers and their infants," the National Center for Health Statistics said.