NEW YORK (AP) — Even as the election outcome intensifies America’s abortion debate, a comprehensive new survey finds the annual number of abortions in the U.S has dropped to well under 1 million, the lowest level since 1974.

The report, which counted 926,200 abortions in 2014, was released Tuesday by the Guttmacher Institute, a research group which supports abortion rights. It is the only entity which strives to count all abortions in the U.S.; the latest federal survey by the Centers for Disease Control and Prevention lacks data from California, Maryland and New Hampshire.

The total from 2014 represented a drop of 12.5 percent from Guttmacher’s previous survey, which tallied 1.06 million abortions in 2011. The decrease was spread nationwide; in only six states did abortions increase over the three-year span.

According to the report, the abortion rate was 14.6 abortions per 1,000 women aged 15-44, the lowest rate since abortion was legalized nationally in 1973 by the Supreme Court’s Roe v. Wade decision.

Following that ruling, the number of abortions in the U.S. rose steadily – reaching a peak of 1.6 million in 1990 – before starting a decline.

The authors of the new report, Guttmacher researchers Rachel Jones and Jenna Jerman, said the latest phase of the decline was likely the result of two main factors: the increased availability of affordable, long-lasting contraceptives that have reduced unintended pregnancies, and the surge of abortion restrictions in many states that have forced some clinics to close and hindered many women’s access to the procedure.

Guttmacher’s state-by-state breakdown showed big declines in abortions in some liberal states, such as California, that protect abortion rights, and also in some conservative states, such as Texas, that have passed laws to restrict abortions.

Jones noted that the majority of women who get abortions have low incomes, and nearly two-thirds are already parents.

“It can be very difficult for them to arrange for time off from work, transportation and child care,” Jones said. “Some of the abortion rate decline is likely attributable to women who were prevented from accessing needed services.”

The highest abortion rates were in the District of Columbia, New York, New Jersey, Maryland and Florida. The lowest rates were in Wyoming, Mississippi and South Dakota, states that had only one abortion clinic operating in 2014. According to the report, the number of abortion clinics nationwide declined by 6 percent – from 839 in 2011 to 788 in 2014.