A quarter of US abortion clinics have closed down in the last five years, a new report from Bloomberg Business has found.

The report, by Esmé Deprez, counts at least 162 abortion clinics that have closed down or stopped offering the procedure since 2011, affecting access for 30.5 million women. The single greatest factor was new legislation.

In the same time period, according to the Guttmacher Institute, a thinktank that supports abortion rights, conservatives swept into power in the 2010 election have helped pass more than 1,000 new abortion restrictions.

Only 21 new clinics have opened. In 2011, Guttmacher counted 553 abortion providers in the US. A net loss of 141 clinics would mean that the number of abortion facilities has been cut by a quarter in the last five years.

“At no time since before 1973, when the US supreme court legalized abortion, has a woman’s ability to terminate a pregnancy been more dependent on her zip code or financial resources to travel,” Deprez writes.

Texas, largely because of a sweeping anti-abortion bill passed there in 2013, lost the most clinics – at least 30. Iowa followed with 14 clinics – all of them Planned Parenthood facilities that stopped offering abortions. Michigan lost 13 clinics.

The closures occurred in 35 states and were not limited to states where Republicans control the legislature. Clusters of clinics closed or stopped offering abortions around Chicago, New York, San Francisco and Washington DC. A dozen closed in California, and at least as many closed across New England.

Those closures indicate the difficulties of operating a clinic even in what seems like friendly territory.

In November, the Guardian reported that abortion clinics in many blue states are struggling to keep their doors open just as much as in red states. One reason is that the bruising fights in red states have prevented them from focusing on subtler challenges in blue states.

But the problem is also one of economics. Because of the stigma attached to the procedure, most abortions take place in standalone clinics. And it can be financially difficult to run an entire doctor’s office just by providing abortions. In the states – mostly liberal – that allow poor women to pay for their abortions with Medicaid, abortion clinics can actually lose money on every procedure.

Deprez counted almost 40 providers that closed as the result of a business decision. Other clinics could not find a provider, had an unfit provider, or closed because of a hostile environment.