Just as several states have amped up their efforts to limit women's access to abortion care, a new report indicates that the number of women actually undergoing abortion procedures in the United States has significantly diminished. According to a new CDC report, the American abortion rate is at an all-time low since Roe v. Wade, and this remains true across all age groups.

The report, which comes out this week and covers the year 2015, is based on data received from 49 reporting areas in the United States. The CDC collects data from all 50 states, plus New York City and the District of Columbia. The abortion rates included are the number of abortions reported to the CDC, per 1,000 women.

From 2006 to 2015, the most recent year for which data is available, the total number of abortions in the United States decreased by 24 percent, per the report. For women aged 15 to 44 years old, that rate decrease was even higher, coming in at 26 percent. This means that, in the last ten years, the number of reported abortions performed in the United States has dropped, dramatically.

There are a number of reasons why experts believe that this drop has taken place. One thing that is certain is that the decline was not sudden — as evidenced by publicly available data, the abortion rate has been dropping for a while.

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In this vein, the year 2014 also marked a historic low for the U.S. abortion rate, according to the Abortion Incidence and Service Availability In the United States, 2014 report, put out by the Guttmacher Institute in March of 2017.

Per Guttmacher analysis of the report, the reasons for this drop may be twofold. On the one hand, access to contraceptives appears to have decreased the rate of unintended pregnancy. But on the other hand, state regulations which restrict abortion access may also be contributing to the falling numbers, per Guttmacher. Clinic closures, especially, according to the study's authors, are likely to make it more difficult for low-income women to access the abortion care they need.

“Abortion restrictions and clinic closures mean that patients may need to travel greater distances to access services,” said Rachel Jones, the lead author of the Guttmacher study. “The majority of abortion patients—75%—are poor or low-income, 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."

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While there may not be a singular reason for the decline in reported abortions in the United States, there is longer-term data available, which draws a bigger picture. Shortly after Roe legalized abortion in the United States, the reported abortion rate went up, for example, according to analysis by The Washington Post, ultimately peaking in the 1980s. Since then, for the most part, the figures have started to trickle down, decreasing from year to year.

Though the courts have repeatedly upheld the legalization of abortion in the United States, its legality faces near-constant challenges by certain lawmakers and interest groups. That's unlikely to change any time soon, meaning that abortion access legislation — and data — is always something to keep an eye on.