Thank you. This explains everything I was attempting to, but does it lucidly. Moreover, it goes in to a lot of things I didn't know about.

Only one thing I have to add: You can find the number of items in a hash with scalar keys %hash, and the number of used/total buckets with ($used_buckets, $total_buckets) = split '/', scalar %hash. With those numbers in hand, you should be able to get more exact timings, or demonstrate to yourself that what pg says is true.