Christianity remains the world's biggest religion while Islam and the non-religious population posted notable increases in the 20th century, according to a major religious reference book. Hinduism showed a slight gain relative to world population during the century, but Buddhism and Judaism lost ground. The biggest declines occurred among traditional ethnic creeds, especially in China and Africa. The trends are reported in the second edition of the "World Christian Encyclopedia" (Oxford University Press), a compilation of statistical estimates and descriptions for each religious group in each nation. "Christianity has become the most extensive and universal religion in history," the encyclopedia states, and has a majority of the population in two-thirds of the world's 238 countries. In addition, "Christianity has become massively accepted as the religion of developing countries in the so-called Third World."....
Source of Text - http://www.eunacom.net/RelStats.htm