That’s approximately how far the abortion rate fell among a group of women in St. Louis when birth control was simply given away for free. The drop in the teen birth rate was even more impressive: 81 percent.

This came out of a study by Washington University in which 9,000 women — many of whom were poor or uninsured — were offered a choice of contraceptives at no cost. Most ended up getting IUDs or other implants, which are the most effective options and are also usually quite expensive.

But the drop in unwanted pregnancies more than made up for the expense. That’s good news for all of us, because we may soon see similar results across the entire country.

The president’s Affordable Care Act now gives access to contraception without co-pays. So never mind trying to overturn Roe v. Wade. If you’re anti-abortion, stand up for Obamacare.