How many people are members of different Christian denominations?

Denominations often form slowly over time for many reasons; due to historical accidents of geography, culture, and influence between different groups, members of a given religion slowly begin to diverge in their views. Over time members of a religion may find that they have developed significantly different views on theology, philosophy, religious pluralism, ethics and religious practices and rituals. As such, in any of myriad ways, different denominations eventually form. In other cases, denominations form very rapidly, either as a result from a split or schism in an existing denomination, or as people from many different denominations share an experience of spiritual revival or spiritual awakening, and choose to form a new denomination based on that new experience or understanding.