0_Apprentice
Hello! I was raised an atheist but at the age of 18 converted to Christianity.
1_Wizard
 It is the world's largest religion, over 2.4 billion in total.
0_Apprentice
What region are you talking about? Americas?
1_Wizard
33% of the global population, not just Americas. But all over the world. 
0_Apprentice
Can you tell me whether the number is growing or declining?
1_Wizard
They make up a majority in over 158 countries, but the actual growth cannot be verified
0_Apprentice
How about the last century? I bet it was more than 33%.