Where did you arrive at your minute percentage data?
I used logic. The birth control pill is designed primarily to prevent ovulation. Secondarily, it is designed to prevent sperm from reaching the uterus. Last, the pill serves to make the lining of the uterus unreceptive to implantation of the fertilized egg (this would be considered abortive). It’s well known that the pill is not perfect at preventing pregnancy.
The following steps must hold true for the hormonal birth control pill to be considered abortive:
1) The pill fails at preventing ovulation.
2) The pill fails at preventing the sperm from reaching the egg.
3) The woman is actively ovulating and fertilization occurs.
4) The pill prevents implantation of the fertilized egg into the uterine wall.
Now, I’m pretty sure that even if a woman is ovulating and has unprotected sex with the intent of getting pregnant, it’s far from a certainty that pregnancy will occur.
You can do the math yourself, but it’s pretty easy to see that the cases where the pill can be considered abortive are extremely rare.