A law professor and associate professor of geography set out to create the most comprehensive map of U.S. payday lenders to date. What they found, to their surprise, was "a surprising relationship between populations of Christian conservatives and the proliferation of payday lenders." And it's not a side effect of a poor population that happens to be Christian, according to the authors: "Our research showed that the correlation between payday lenders and the political power of conservative Christians was stronger than the correlation between payday lenders and the proportion of a population living below the poverty line."

http://www.csun.edu/%7Esg4002/research/usury.html