The Institute also houses the Urban Institute -Brookings Institution Tax Policy Center, the National Center for Charitable Statistics and Urban Institute Press.

Americans in general give about 2 percent of their income to charity each year, with nearly half of that going to religious organizations, according to research by the National Center for Charitable Statistics.

Additionally, requests may be made via the IRS using Form 4506-A, and PDF copies can often be found online on sites such as Foundation Center's 990 Finder, Guidestar.org and the National Center for Charitable Statistics.

In 2001, the 400 largest controlled $76.7 billion in assets, according to the National Center for Charitable Statistics at the Urban Institute, a research group.

The National Center for Charitable Statistics (NCCS) is a clearing house of data on the U.S. nonprofit sector.

Mr. Sanford's gift is greater than the total assets of $256 million held by South Dakota's 126 foundations in 2004, according to data compiled by the National Center for Charitable Statistics.

The National Taxonomy of Exempt Entities (NTEE) classification system was developed by the National Center for Charitable Statistics to classify nonprofit organizations.

National Center for Charitable Statistics, Cheyenne Elders Council Inc.

Linda Lampkin, program director of the National Center for Charitable Statistics at the Urban Institute in Washington, said she would not be surprised if the rate had increased since 2000, the last year with available figures.

Data gathered by the National Center for Charitable Statistics indicate total giving, adjusted for inflation, has been declining since 1989.