Share of world population.

Christianity

1910: 34.8%
2010: 32.8%

Islam

1910: 12.6%
2010: 22.5%

Hinduism

1910: 12.7%
2010: 13.8%

Agnosticism

1910: 0.2%
2010: 9.8%

Chinese folk religion

1910: 22.2%
2010: 6.3%

Buddhism

1910: 7.9%
2010: 8%

(World Religion Database)