What are the religions and religion sects, present in the US...and what are the overall percentage of the US population (approximately)?

1) What are the religions and religion sects, present in the US...

Unknown. I doubt very much that even the Federal Government knows, as new sects and new religions sprout up every year.

2) what are the overall percentage of the US population (approximately)?

This is a pretty reliable source:

https://www.cia.gov/library/publications/the-world...

Protestant 51.3%, Roman Catholic 23.9%, Mormon 1.7%, other Christian 1.6%, Jewish 1.7%, Buddhist 0.7%, Muslim 0.6%, other or unspecified 2.5%, unaffiliated 12.1%, none 4% (2007 est.)

And so is this (which provides more recent and more detailed data):

http://www.pewforum.org/2015/05/12/americas-changi...