Certainly, the Catholic Church is probably over-inclusive when it comes to who it includes in its numbers. But that's probably done by every other denomination. So, it doesn't likely change the percentages much.
I know of no non-catholics that place any value in what the vatican proclaims,
So, non-Catholic Christians do not agree with Vatican on issues of abortion, gay marriage etc.?
I agree that over-inclusion is not limited to the catholic church. Although, your assumption is that the over-inclusion is at a relatively equal rate between catholics and non-catholics. I don't believe that to be a sound assumption, but in all honesty neither of us know the hearts of 2 billion people so neither of us have the ability to present something approaching proof on the matter...simply evidences that would seem more anecdotal (and they would likely be accurate in both directions)
So, non-Catholic Christians do not agree with Vatican on issues of abortion, gay marriage etc.?
There is some agreement on these issues, however the source of the agreement is only to the extent that the vatican agrees with the Bible. That is to say, any agreement from non-catholics is not based upon it being proclaimed by the vatican but rather because it is found in the bible.