According to a national study conducted in the United Sates, 2005 saw the lowest number of abortions since the procedure became legal 35 years ago.
The Guttmacher Institute, which researches issues pertaining to reproductive health and sexuality, said there were about 1.2 million abortions in 2005 -- 25 percent fewer than in 1990, when they reached an all-time high of 1.6 million.
In 2005, the US abortion rate was 19.4 abortions for every 1,000 women between the ages of 15 and 44, according to figures compiled from surveying abortion providers. The 2005 figure represented an eight percent drop from the number of abortions in 2000.
The finding underscores a continued downward trend that started after the abortion rate peaked at 29.3 procedures per 1,000 women in 1981, according to the institute.
Despite the drop, slightly more than one pregnancy in five ended in abortion in 2005, the Guttmacher Institute said.
"Our policymakers at the state and federal levels need to understand that behind virtually every abortion is an unintended pregnancy, so we must redouble our efforts towards prevention, through better access to contraception," said Sharon Camp, president and chief executive officer of the Guttmacher Institute.
The last time the numbers were lower was in 1976 -- three years after abortions were legalized in the United States -- when 1.18 million abortions were performed.
But even as the rate of surgical abortions declines, the study found that the use of "early medication abortions" increased dramatically between 2000 and 2005, with growing numbers of providers offering surgical abortion services.
About 57 percent of all known abortion providers now offer medication abortion services, compared with 33 percent in early 2001.
The Guttmacher Institute said medication abortions accounted for about 13 percent of all abortions performed in 2005, and about 22 percent of all abortions performed prior to nine weeks' gestation.
Six percent of pregnancy terminations involved mifepristone, an "early medication abortion" drug approved by the Food and Drug Administration in 2000.
"As knowledge about and comfort with mifepristone has increased, it likely has been introduced into settings where surgical abortions were previously not provided, e.g. family planning clinics and the practices of family doctors," the report said.
It also noted that the number of abortion providers has fallen steadily since 1982, when there were 2,900 facilities that offered abortions, to around 1,800 in 2005.
Abortions were also taking place earlier in the pregnancy, thanks in part to the availability of early medication abortion, said Rachel Jones, the survey's lead researcher.
"For a long time, nearly 90 percent of abortions in the US have taken place in the first trimester, but in recent years, women having an abortion have been able to do so earlier and earlier in the first trimester," Jones said.
Three in 10 abortions take place "at six weeks or earlier," she said.
"Medication abortion, which provides women with an additional option early in pregnancy, reinforces this very positive trend."
The report was released days before the 35th anniversary of the Roe versus Wade decision by the Supreme court, which legalized abortion in the United States.