christianity is a abrahamic monotheistic religion 
It's one of thousands of religions
Yes that's very true.  It is the worlds largest religion with over 2.4 billion followers 
That surprises me, I would have thought Muslim was bigger
I honestly thought the same thing.  Its pretty crazy to think christianity covers 33 percent of the population 
I wonder if overall membership is currently declining or growing at the present time?
Not much information on that but i did find another fact is that they believe that Jesus is the son of god and savior of hummanity