What is the population of sunni religion?

First, you have to understand that there is nothing called Sunni Religion.

Sunni Are Muslims who follow the footsteps of the prophet Mohamed PBUH, they are 90% of the Muslim population.

Shiite are Muslims also, but they have different approach or understanding in the practices, but both worship the one and only god and believe in Mohamed as the prophet and messenger of Allah.

Saying so, the total population of Muslims world wide is 1,226 million.Check the sources on http://www.religioustolerance.org/worldrel.htm