These graphs show trends in favoring abortion for any reason since 1977 (GSS data). Liberals and extreme liberals were combined in the the top chart, and it shows that this radical position has increasingly become a part of a liberal orientation. Back in the 70s liberals were split on the issue. It's the norm now to be an extremist.
The bottom graph combines conservatives and extreme conservatives. For them, licentious abortion has always been a minority view. There has been a decrease, but it's not as noticeable.