You might not know it from the political debate, but abortion is becoming increasingly rare in the United States — and activists on both sides are rushing to take credit. A survey released earlier this week by the Associated Press shows that the number of abortions performed each year declined by about 12 percent nationwide between 2010 and 2014, continuing a steady downward trajectory since the early 1990s.

Anti-abortion activists point to the hundreds of inventive restrictions on abortion passed in Republican-controlled states across the South and Midwest since 2010, which have closed dozens of clinics, especially in rural areas. These restrictions include mandatory pre-abortion counseling, waiting periods and policies that require women to look at an image of the fetus before undergoing the procedure. Charmaine Yoest, the president of Americans United for Life, one of the groups behind the measures, argues that the laws are forcing women to consider the full implications of the decision to abort. She told the AP that the decrease in abortions is a sign that women’s perspectives are changing. “There’s an entire generation of women who saw a sonogram as their first baby picture,” she said. “There’s an increased awareness of the humanity of the baby before it is born.”

Abortion-rights advocates, meanwhile, argue that the abortion rate is declining because contraception is cheaper and more widely available than ever before, thanks to the Affordable Care Act, which requires insurers to cover most types of birth control with no copay.

Although it’s impossible to attribute the decline to a single factor, the data shows that better contraception — combined with a bad economy and a falling teen pregnancy rate — is largely responsible. Abortion rates did fall in many of the states with new restrictions, but they also dropped in others, such as New York and Connecticut, where access to abortion is relatively unobstructed. In fact, some of the states with the biggest declines — Hawaii, Nevada and New Mexico — have enacted no new abortion laws in recent years, suggesting that something other than reduced access is spurring the trend.

Elizabeth Ananat, an associate professor of economics at Duke University who studies the economics of fertility, said the data also contradicts the notion that more women are rejecting abortion and choosing to stay pregnant. “If women’s attitudes were really shifting, we should see the birth rate go up,” she says. “Instead, birth rates are falling, too.” (The birth rate reached a record low in 2013, according to the CDC. It fell by 2 percent between 2010 and 2013, and by 9 percent between 2007 and 2013.) According to Ananat and other experts, the decline in abortions is a symptom of another trend: Fewer women are getting pregnant in the first place.

What’s behind the declining pregnancy rate is more difficult to pinpoint. One clear factor, said Joerg Dreweke, a spokesman for the Guttmacher Institute, a research organization that supports abortion rights, is the teenage pregnancy rate, which has been falling steadily since the early 1990s. According to Dreweke, this is partially due to better contraceptive use among teenagers. Other research on teen fertility rates supports this: In a paper published earlier this year, economists Phillip Levine and Melissa Kearney found that other policy changes — such as sex education, whether it was comprehensive or abstinence-only — couldn’t explain the decline. Because the vast majority (82 percent in 2010) of teen pregnancies are unplanned, a reduction in teen pregnancy overall will have an effect on the abortion rate. Since teenagers account for only about 18 percent of abortions, though, their effect is limited.

Another likely explanation of the declining pregnancy rate — and by extension the declining abortion rate — Ananat said, is that the lingering effects of the economic recession are prompting more women to consider whether now is the best time to have a child, especially women in their 20s, who account for 57 percent of all abortions. After climbing in the earlier part of the decade, the U.S. birth rate took a nosedive around 2008 along with the abortion rate, suggesting that hard times were prompting more reproductive caution. “People think of pregnancies as being either planned or unplanned, but there’s sometimes some middle ground there, some ‘let’s see what happens,’” she said. “People’s ambivalence tends to evaporate during a recession, and they’re more careful about birth control use because they’re more certain they don’t want to get pregnant.” This economic uncertainty even trickles down to teenagers. Kearney and Levine found that the jump in unemployment during the Great Recession was associated with a modest reduction in teen pregnancy.

But there’s a final explanation: So many women are able to successfully avoid pregnancy at least partly because of the Affordable Care Act’s contraception mandate, which took effect in 2012 and minimizes the up-front costs for highly effective, long-lasting forms of birth control such as the intrauterine device (IUD) or hormonal implant. The number of women using the most effective forms of birth control jumped to a high of 12 percent by the end of last year. New research shows that women who live in states with less abortion access are more likely than women who don’t to use a contraceptive like the IUD. “There’s been a push to expand the IUD and implant to women who were using contraception ineffectively in the past because long-acting birth control had big up-front costs, and they couldn’t afford it,” Ananat said. Because women who use contraception incorrectly or inconsistently account for 41 percent of unintended pregnancies, even a small shift to highly effective methods of contraception could have a disproportionate effect on the abortion rate.

What the data shows, according to Ananat, is a kind of perfect storm. “The teen pregnancy rate has been declining for a while now, and we can’t say that’s the driving force, but it’s contributing,” she said. “And then you have the combination of the recession, which makes people less willing to have children, and the Affordable Care Act, which gives women better access to contraception at a time when they really want it. So you end up with a situation where there’s less of a need for abortion just because fewer women are getting pregnant.”

The question, for her, is whether new abortion laws are affecting when women are getting the procedure. Over the past decade, more and more women have opted for abortions early in their pregnancies, but as states place more barriers in their way, that trend could shift. If women have to jump through more hoops — travel to faraway clinics or encounter waiting periods that require overnight stays — they might delay the procedure until they can raise enough money or take time off work. “We know that restrictive policies don’t deter most women from getting abortions, but it can delay them,” Ananat says. “The idea that women’s attitudes toward abortion are changing, though — we just don’t have evidence for that.”