Try searching under specific series titles to get a better picture of how much filesharing might be impacting upon Brandon's bottom line.
The newest dodge I've seen is subtly changing the title, so 'Baker's Dozen' would become something like 'Cook's Twelve', Jules Jordan's 'Slut Puppies' would become 'Whore Doggies' etc.
The industry needs to start cracking the whip on the uploaders. If nobody uploads the content, then nobody can download the content. If you want to chop down a tree, you don't chop off every individual branch and twig, but instead go straight for the trunk.
I'm currently working on a content tracking idea which would allow producers to identify the uploader, regardless of whether they chop the clip up, use a proxy etc.
Whilst sound, unfortunately said idea would not work within the standard '$30 a month and download as much as you like' business model.