Here's a statistic.....not sure how they can attribute all these dogs to mills, but mills certainly spike the numbers.
"Puppy mills mean big revenues for the AKC. In 2006 the American Kennel Club (AKC) registered 870,000 individual dogs and 416,000 litters. At $20 per dog and $25 per litter (plus $2 per puppy), AKC brought in well over $30 million in revenues from registration of dogs born in puppy mills".
From this link...
Rally Against The AKC's Support Of Puppy Mills