U.S. abortions fell 5 percent during the recession and its aftermath in the biggest one-year decrease in at least a decade, perhaps because women are more careful to use birth control when times are tough, researchers say.

The decline, detailed on Wednesday by the Centers for Disease Control and Prevention, came in 2009, the most recent year for which statistics are available. Both the number of abortions and the abortion rate dropped by the same percentage.

Some experts theorize that some women believed they couldn’t afford to get pregnant.