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
Yes especially the Jehovah's Witnessess, I think they give extra attention to Jesus
Very true, another fact is that Originating in the roman province of judea, it quickly spread to europe and various other countries.
And then right across the whole globe through missionary work