It's not certain that the study should be relied upon. Attributor is in the business of selling anti-piracy monitoring for content providers, and the more piracy they find the more they can justify their existence.
Following on a series of assumptions laid out in great detail, they think piracy is a $3B threat right now.
Well, that sounds a bit steep to me.
But none of us really know, and I'll put it out there with the aforementioned caveats.