Fleet Sizes

I am thinking of expanding my fleet at the moment and it goit me onto thinking
about 'realistic' fleet sizes.

I was thinking that each 'power' such as NAC, NSL etc would have limited
resources and budget (much like no) plus there is the balance between domestic
and military spending so I was trying to guess just how many space ships do
the NSL have in thier fleet?

I was wondering if anyone has any idea what the current wet anvy sizes are for
the US, UK and German Navy. I though tthis may give me a couple of pointers in
the right direction. OK so space is bigger and more area needs patrolling, but
I was just curious about fleet compositions.