Okay, I don’t have the stats to hand. I do recall seeing a study a while back, but I can’t find it, and you can’t use the raw stats because of the different availability of abortion services in different states skew the states.
So I withdraw that comment, but it remains undeniable that given the tiny proportion of atheists in the US population (less than 10%), blame for the vast majority of the abortions in the US must be be laid at the feet of believers. If there was no supply, there would be no demand.
I would agree with you that so-called believers have not done enough to prevent abortion, absolutely. But I would argue the percentage of practical atheists is higher than 10% consisting of liberal Christians, agnostics, and the like. I believe the 10% figure is more likely those who openly profess themselves Atheists. And even the 10% figure is probably a bit high because I don't truly believe all Atheists are faithful to their atheist religion when the chips are down.