Weekly music charts for 2016

[Music Head]

Charts are made up from streaming, digital and physical purchases.

bet you are getting tired of me bringing this up
my confusion this time has to do with
why there are zero singles (other than from the new album) on the U.S. chart
yet there are old singles on the others
in the digital age how are different countries charts even distinguished?
example: if I download a Bowie song, whose chart does it show up on?
does it depend on where I reside or where I purchased it from?
I have always questioned the validity of charts