If u had to guess... How many "doors" to houses, apts, dorms, businesses are in America?

Question

are perhaps.. in the world

Answer 1

More than I would want the job of counting, no matter what the payrate.

Answer 2

America has 300,000,000 people
so let's say 5 doors each
1,500,000,000
But for the wide world, 3 doors each,
at 7,000,000,000
21,000,000,000

1/5 of the world's people live in one room homes, I would venture to guess.