@KenS
For started, yes, legal abortion have been falling since the late 80's in the US. Second, your source doesn't make a per capita ratio either nor does it adjust for the population in age to reproduce. In the early days of Roe v Wade, the population of the US was a 100 000 000 people lower for example. Furthermore your source is for the general US population. It doesn't make a difference between the States with more or less restriction and availability of the service nor does it compare it to other countries in the world.
In other words while those information are accurate despite being pulled from a highly partisan source and certainly interesting it doesn't have any impact, positive or negative on my position. At best, it could reinforce the idea that legalizing abortions doesn't make abortion more or less abundant. Other factors are at play there.