Public opnion polls are typical sources of statistcs on people's beliefs. Search these databses using keywords to find opinion poll questions that ask about them.
A weekly briefing of public opinion poll results from Gallup. This link allows you to browse through several years worth of this publication via EBSCO. Covers 1996-present.
Note: Click on the "Search within this publication" link to do a keyword search limited to the Gallup Poll Briefing. It may help to use the Advanced Search option and select SmartText Searching as the search mode.