Abortion rates are at an all-time low in the developed world, having dropped by more than 40 percent over the past 25 years. But in developing countries—many of which have outlawed abortion and make contraception difficult to access—the rate of abortions has stayed nearly constant, according to a new report from the Guttmacher Institute and the World Health Organization.

The new estimates, published Wednesday in the Lancet, provide another bit of evidence that criminalizing abortion does not curb the practice. In countries where abortion is completely illegal or permitted only to save the life of the pregnant woman, the most recent data places the average annual abortion rate at 37 per 1,000 women aged 15 to 44. In countries where abortion is legal in most cases, the rate is 34 per 1,000 women.

“The obvious interpretation is that criminalizing abortion does not prevent it but, rather, drives women to seek illegal services or methods,” wrote Diana Greene Foster of the University of California’s Advancing New Standards in Reproductive Health in a comment linked to the report. “But this simple story overlooks the many women who, in the absence of safe legal services, carry unwanted pregnancies to term.”

Part of the reason why abortion rates in these anti-abortion countries are so high is the fact that contraception, sex education, and other family-planning services are usually similarly hard to obtain. Where there’s little contraception, there are more unintended pregnancies; where there are more unintended pregnancies, there are more abortions. Those who don’t get one of these often unsafe illegal abortions, carrying their unwanted pregnancies to term, bear a higher risk of maternal mortality and may be condemned to a cycle of poverty driven by a growing family they can’t afford.

In addition to comparing abortion rates in countries where abortion is legal with those of countries where it is illegal, the researchers found stark differences between developed and developing nations. In the developed world, between 1990 and 2014, the average annual abortion rate per 1,000 women fell from 46 to 27, a drop made most drastic by Eastern Europe. There, modern contraception (as opposed to traditional contraceptive methods like withdrawal and the rhythm method) has long been hard to get, of questionable quality, and largely ignored by the political and medical establishment, while abortion services have been cheap and unrestricted. But in the past 25 years, as modern contraception saw a surge in popularity and accessibility, the abortion rate in Eastern Europe fell from 88 per 1,000 women to 42.

Every other region in the developed world saw lesser but still significant decreases in the abortion rate: Southern Europe’s rate fell from 38 per 1,000 women to 26; Northern Europe’s from 22 to 18; and North America’s from 25 to 17. Meanwhile, in developing countries, the abortion rate saw only a slight decrease between 1990 and 2014, from 39 abortions per year per 1,000 women to 37.

“In developed countries, the continued fall in abortion rates is largely due to increased use of modern contraception that has given women greater control over the timing and number of children they want,” author Gilda Sedgh said in a press statement. “In developing countries, however, family planning services do not seem to be keeping up with the increasing desire for smaller families. More than 80 percent of unintended pregnancies are experienced by women with an unmet need for modern methods of contraception, and many unwanted pregnancies end in abortion.”

As a proportion of pregnancies, the global abortion rate has remained somewhat constant over time; the 2010-2014 average was 25 percent. The concurrent rate in Latin America, home to some of the most punishing anti-abortion laws in the world, was 32 percent—the highest of all the regions. Now that the fast-spreading, microcephaly-causing Zika virus has taken hold in many of these nations, the need for family-planning services is even more acute. Unfortunately, U.S. legislators aren’t doing much to help—the Helms amendment prevents the U.S. from providing foreign aid for abortions, and Republicans have recommended that Zika-infected women accept microcephaly rather than terminate their pregnancies. The clear answer here is contraception aid. If policymakers in the U.S. truly want to prevent abortions in Latin America and elsewhere, they should heed the wisdom inherent in these new numbers: Improved contraception access gets results where draconian laws fail over and over again.