The report from the Guttmacher Institute in New York found there were 1.1 million abortions reported in the United States in 2011, the New York Times reported. That is about 16.9 abortions for every 1,000 women of childbearing age.
The rate was 29.3 abortions per 1,000 women in 1981, the peak level in the United States, the private abortion rights research group said.
The rate was 19.4 per thousand in 2008, the last year a similar study was previously conducted.
The Times said while the report did not include a detailed examination of the reasons for the downward trend, the researchers said it coincides with the growing use of effective long-term contraceptives such as intrauterine devices. Study authors Rachel K. Jones and Jenna Jerman suggested the rate also could be affected by the recession and economic uncertainty, the Times said.
The authors concluded the drop in the rate was not attributable to any large extent on anti-abortion laws.