Here is an interesting poll for you: an American one on Catholics's attitude to gay marriage. Interestingly it did what most polls on such issues do not do: it distinguished between Catholics who go to Mass and Catholics who do not. The findings are revealing: among Catholics who go to Mass a majority are opposed to gay marriage.
Of course that is not surprising: those who practice their Catholic faith are more in touch with its teachings, are more inclined to understand them and will be more faithful to them. Those who do not go to Mass have established a distance from the Church and her teachings, and will be less inclined to accept or live them. That is an important point to note when it comes to issues of controversy, particularly moral issues which are at odds with the prevailing ideologies of relativism and secularism.
So if a journalist or statistician wants to hear what Catholics think on issues, where do they go? They are supposed to take a representative sample - but a representative sample of whom? Catholics who believe and practice or Catholics who do not believe and do not practice? Given the ideology which dominates at the moment they may be inclined to go to those who do not practice in order to get the results they want. But if they are not ideologically driven and want a true picture, they may well need to begin distinguishing between those who practice and those who don't. So perhaps the first question they need to ask in the poll is: "Do you go to Mass every week?"
Of course this brings us to another, larger issue: what does it mean to be Catholic? Now there's a controversial question.