Keep in mind, PH1221, there's a reason why NGC makes people pay for access to those numbers. They're going to be pretty unhappy with a member who shares them publicly anyway.
With that said, register at Heritage Auctions (ha.com). That registration (free) will give you access to their archive of past auctions, most of which include population numbers at the time of the auction. It will also expose you to pricing data, and for issues like this you'll probably be able to buy them at Heritage for much more consistent prices than you might from
ebay and the like.