I hope this is correct

Odds of any given player having AA whilst you hold KK is 4/50 * 3/49 = 0.0049 or 0.49% (about 1 in 200)

Now the odds of anyone having AA is 1 - the odds that everyone missed AA. At a 10 seat table that would be .....

1 - (0.995*0.995*0.995*0.995*0.995*0.995*0.995*0.995*0 .995) = 0.0432 or 4.32%

So any time you were not dealt an A, at a full table someone will have AA aproximately 1 in every 23 hands.