Alternative summary listings of major world religions and numbers of adherents:
Christian Science Monitor (1998): Top 10 Organized Religions in the World
Encyclopedia Britannica's Adherents of All Religions by Six Continents
Tigerx.com's Top 10 Religions - A casual but insightful attempt divided along the lines of functional religious cultures rather than classical categorization
Minnesota State University's "Religions of the World" website lists the "world's six major religions" as: Islam, Judaism, Buddhism, Animism, Christianity and Hinduism. Read the site's introduction