from #71:
That's not the significant factor. Reductions in the states that did not have additional restrictions, which produced most of the reduction, didn't have changes in the abortion law. The states which made abortion laws more restrictive probably reduced access to contraception as well.
It's not the only factor, but it's worth considering. If the 28 states plus DC performed 80% of US abortions in 2011, abortions dropped (say) 20% by 2014 with 62% of that decrease in those 29 jurisdictions, they performed 84.5% of abortions in 2014. Simple arithmetic; though my numbers above are purely hypothetical, the math isn't. As an extreme (and impossible at present) example, if there were a state that had zero abortions performed in 2011, one might claim that the abortion restrictions there weren't working because they brought no decrease. With no total-abortion context, that 62% share tells us very little about the effect of states' abortion regs.