There are many sources of statistical information on virtually every topic, but no single tool to find them. One way to tackle discovering stats is to think about who would be interested in collecting data on a particular topic and producing statistics about it. On this page you'll find some of the usual suspects and resources/tools for finding statistical information produced by them.
The collection and publication of data and statistics is also a business. Many commercial firms (think pollsters, marketing firms, trade organizations, etc.) produce this kind of information - for a fee - for various industries. One strategy for discovering this kind of statistical information is to search Discover (includes trade publications!) or one of our many news databases using a combination of keywords on your topic and the terms statistics or poll or survey or report. When you find an article referencing statistics, a poll, survey, or report, note its name and the name of the organization that produced it. Try searching on that information in Google to see if any of it is available for free. If not, try searching the Discover to see if we have it, or WorldCat to see if it's available at another library and request via interlibrary loan.