People seeking an abortion are "highly motivated" to travel if they can't get abortions where they live.

That's one conclusion from a study from the Guttmacher Institute, a research and policy group that supports reproductive rights.

Here's one striking finding: in Illinois, there were 18,300 more abortions in the first half of this year compared to 2020.

"If you're interested in where people are going, then I think the numbers tell a big part of that story because it represents a lot of people traveling," says Isaac Maddow-Zimet, a data scientist at the Guttmacher Institute.

Illinois already provided a lot of abortions in the past, and the number increased by 69%.

"The percentage increase, I think, is also important because it does speak to the potential strain this puts on providers capacity to provide care," he says.

In New Mexico, there was a whopping 220% jump in the number of abortions.

Both New Mexico and Illinois have enacted laws to protect access to abortion. Their geography is another key factor.

"What we're seeing is really big increases in states that border ban states," Maddow-Zimet says.

There were also small increases in states bordering ban states that have not positioned themselves as havens for access, including in Montana and Wyoming, which border the Dakotas. Ohio, which has its own ban on hold, also saw a slight increase. It borders Kentucky and West Virginia, which have no abortion access.

States with abortion bans do allow an extremely small number of abortions, if they meet certain exceptions. This year in Texas, for instance, there have been four abortions on average each month — in 2020, that number was about 4,800 per month. (A lawsuit alleges that Texas's medical emergency exception is too narrow and prevents or delays care that's medically indicated.)

To estimate how the number of abortions has changed in each state, Guttmacher got data from a sample of providers every month and combined it with historical caseload data to create a model estimating abortion counts for January to June of this year. Then, for each state, researchers compared that estimate with the number of abortions provided in 2020, divided by two to represent a comparable six-month period.

One big caveat of this research is that it only measured abortions that happened in clinics, hospitals and doctor's offices, Maddow-Zimet says. "We do not attempt to measure counts of self-managed abortions, where somebody might be, for example, ordering pills from a pharmacy outside of the U.S., or obtaining them from a community network," he says.

He also notes that not all of the changes can be traced directly to last year's Supreme Court decision that overturned Roe v. Wade. "2020 was a long time ago and a lot has happened since then," he says. The COVID pandemic, and expanded telehealth, and a trend of increase in overall abortions that had already begun, all no doubt contributed to how state abortion numbers have changed to different degrees.

Guttmacher has put all of this data online, and they plan to keep updating it in nearly real time, Maddow-Zimet says. Soon they will publish data showing how new bans in Indiana and South Carolina, and a 12-week ban in North Carolina further change how people move around the country to access abortion.

Edited by Diane Webber; Graphics by Alyson Hurt