What is The Biggest Religion(in population) in The World?

This is what I could come up with. I found it at; http://www.adherents.com/Religions_By_Adherents.html#MainList 1. Christianity: 2.1 billion 2. Islam: 1.5 billion 3. Secular/Nonreligious/Agnostic/Atheist: 1.1 billion 4. Hinduism: 900 million 5. Chinese traditional religion: 394 million 6. Buddhism: 376 million 7. primal-indigenous: 300 million 8. African Traditional & Diasporic: 100 million 9. Sikhism: 23 million 10. Juche: 19 million 11. Spiritism: 15 million 12. Judaism: 14 million 13. Baha'i: 7 million 14. Jainism: 4.2 million 15. Shinto: 4 million 16. Cao Dai: 4 million 17. Zoroastrianism: 2.6 million 18. Tenrikyo: 2 million 19. Neo-Paganism: 1 million 20. Unitarian-Universalism: 800 thousand 21. Rastafarianism: 600 thousand 22. Scientology: 500 thousand

I am moeslem and I believe someday, Islam will be the biggest religion in the world.

Today the religion which is followed and practiced is Islam. We see muslims pray five times in a day and keep one month fast and spend money in charity and believe in day of judgment. But i see fewer christians follow their religion.