Define what you mean by "known". If person A "knows"
one set of primes, and person B "knows" a different set of
primes, is the union of the two sets "known"?
If I have a computer program that generates them
internally, but never prints them, are they "known"?
Does known mean "published"? I can't imagine why anyone
would want to publish a large list of primes. It would
be pointless.
And by any measure, the number "known" is far greater
than 1 billion. I can generate that many in ~20 minutes
on my laptop.
Your question is ill-conceived and not well defined.