Source of classification. Located at the Glenmary Research Center website: Religious Congregations & Membership 2000 (c) 2002 by Association of Statisticians of American Religious Bodies (ASARB).
I note that some members of the Lutheran Family of denominations fall into the Evangelical Protestant category and others in the Mainline category.
Most Complete Data on U.S. Religious Affiliation Released
149 religious bodies, including Muslims, report 140 million adherents
Nashville, Tenn. (Sept. 20, 2002)—The most complete data available on U.S. religious affiliation was released Sept. 20, 2002, at a press conference preceding the Religion Newswriters Association’s national conference ..., published by the Glenmary Research Center (Nashville, Tenn.), is the latest in a series of every-10-year studies conducted at the same time as the U.S. census. For the first time, data on Muslims and other religious bodies beyond the Judeo-Christian tradition is included, although on a limited basis.
... Like all previous reports in this series of studies on U.S. religious affiliation, data are reported by region, state and county. The last report, Churches and Church Membership in the United States: 1990, included data on 133 church/congregational groupings. The 2000 study and its publication are made possible by a grant from the Lilly Endowment. Inc.
brings together statisticians and researchers who collect and publish information about denominations and other faith groups in the United States. Every ten years, ASARB compiles the Religious Congregations Membership Study, providing the most comprehensive portrait of religious affiliation throughout the United States.Mission Field Counties as identified by Glenmary Research Center.