Question for stats gurus - odds of KK vs. AA

[LuvDemNutz]

After 73,000 hands of No Limit on Party Poker and skins I have been dealt KK 345 times.

Of those 345 times I have come up against AA 11 times.

These 11 times are hands that have gone to showdown - they obviously do not include times where I folded before the river.

So the true number is probably 13-15.

My question is statistically is this the amount of times, on average I should expect to come up against AA when dealt KK. (About 1 in 23-28 times).

If not, can anyone estimate the odds of coming up against AA say, 13 out of 345 times I am dealt KK?


Also, is my sample too small or biased in any way?

Thanks.