Well, I had no idea, I haven't spoken on pro-life issues since the '80's. So I did some research.
The Alan Guttmacher Institute promotes "No woman is completely free unless she is wholly capable of controlling her fertility and...no baby receives its full birthright unless it is born gleefully wanted by its parents." - and the statistics I'm listing came from their research in the '90's.
"Why women have abortions
1% of all abortions occur because of rape or incest; 6% of abortions occur because of potential health problems regarding either the mother or child, and 93% of all abortions occur for social reasons (i.e. the child is unwanted or inconvenient)."
So if I'm reading this correctly, 93% of the 1.37 million (1996 stat) abortions could be prevented if women would control their fertility before the conception.