Religionists, 1.31%. The world is becoming more religious, not less.
Christians, 1.3% vs. Muslims, 1.8%. Both Christians and Muslims are gaining ground in the world, but Muslims are gaining ground faster. This is largely a function of faster net demographic growth rates in countries that have large Muslim populations; this in turn is caused partially by declines in mortality.
Hindus, 1.26%. The Hindu population is making gains worldwide, but not as fast as Christians or Muslims.
All of the remaining groups (except the very small Sikh population) are declining vs. global population.
Non-religionists, 0.3% – agnostics are growing at .36%, and atheists at 0.05%. Despite headline-grabbing trends in certain parts of the world (the West, mostly), the world as a whole is becoming progressively and massively less non-religious (and atheists in particular are in sharp decline).