"Conversion" Rates

I have been browsing the site for quite some time, and a question occurred to me. It would seem that we all want to be united, as that is what Jesus taught. This is one of the reasons why we evangelize and live our faith. The more I dive in and learn more about my faith, the more conversion stories I here about people coming into the Catholic Church. Of course, on this site (and of course elsewhere in the world), there are people who have left the Church for one reason or another. So my question is: Does anybody know the approximate rate of conversion of people into the Church vs. people leaving the Church? If so, how does it compare? How has it changed, if at all, over the last century? There are a lot of issues to deal with, but are we becoming increasingly united?

Pew Research seems to be the most quoted/cited for figures such as those:
You can dig into their data sets here: pewforum.org/data/

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