Islam is widely touted as "the fastest growing religion in the United States," so how does one explain that The World Almanac and Book of Facts has these figures for Muslims in the United States:
1997 edition (p. 644) says 5.1 million
2003 edition (p. 635) says 2.8 million
No, the population did not actually decrease; to understand this reduction in the estimate, see my October 2001 analysis, "How Many U.S. Muslims?" In brief, the almanac stopped accepting the overblown Islamist estimates as accurate and instead relied on the scholarly and reliable work of the American Religious Identification Survey 2001 and Tom Smith of the University of Chicago. (April 22, 2003)
Aug. 15, 2003 update: Using information from 1990 and 2000 national censuses, John R. Logan and and Glenn Deane find under 2,900,000 Muslims living in the United States.
June 10, 2004 update: Islamist organizations, however, continue to make fantasy claims. Today the Islamic Society of North America issued a press release indicating that it represents "10 million American Muslims." Of note too is the statement by a journalist in the Seattle Post-Intelligencer (in February 2001), presumably influenced by one of the Islamist sources of the article, that Islam is "the second-most popular religion after Catholicism" in the United States.
Oct. 15, 2004 update: Abdel Rachid Mohammad, the first Islamic chaplain in the U.S. armed forces, tells Agence France-Presse, that there are eight to ten million Muslims in the United States. Given his official capacity, this inflated number is especially unfortunate.
June 14, 2005 update: In an undated commentary on the homepage of his organization, The Mosque Cares, W. Deen Mohammed writes that "Partly through conversion but mainly through immigration, the number of Muslims has now risen to three or four million." What a refreshing change from the boosterism of the Islamists. (Also of note is that he uses the spelling G-d, as in "there is but One G-d and one human family."
June 21, 2006 update: "There are almost 8 million Muslims in America," asserts Daisy Khan, executive director of American Society for Muslim Advancement, in a puff-piece produced by the U.S. Department of State.
Oct. 31, 2006 update: Baron Bodissey of Gates of Vienna has the interesting idea in "The Numbers Game" to extrapolate from U.S. experience and slash boosterish estimates for Muslim populations around the world by 1/3. Instead of 21 million Muslims in western Europe, for example, he counts 13.5.
The Pew study projects approximately 1.5 million adult Muslim Americans, 18 years of age and older. The total Muslim American population is estimated at 2.35 million, based on data from this survey and available Census Bureau data on immigrants' nativity and nationality. It is important to note that both of these estimates are approximations.
Feb. 22, 2008 update: Pew offers another estimate in its "U.S. Religious Landscape Survey," where it finds the U.S.-based Muslim population to be 0.6 percent of the total. Given that latter is about 300 million, the Muslim population would be about 1.8 million.
Apr. 16, 2007 update: Newsweek's Lorraine Ali writes of "the nation's 8 million Muslims."