The list of top submitted sites is not a list of the sites users are most interested in. In some cases the site owners submit every post, but many never get enough upvotes to make it onto the front page. To find the sites users are most interested in, you want not the raw number of posts per site, but the number that get over some threshold of points.
>>chengm+T
Yes, much better. The total submissions/total points are skewed by sites (TC) and blogs (CodingHorror) that post every day, sometimes multiple times per day. If you get enough at-bats, you'll get a lot of hits.