I havent actually ever seen it drop myself http://www.zeropaid.com/news/9818/P2P+Traffic+Expected+to+Grow+400%25+Over+Next+5+Years
Every so often we get a new study that makes new claims and predictions regarding P2P traffic. Add to the list a recent one by Multimedia Intelligence entitled "P2P Networking: Content’s “Bad Boy” Becomes Tomorrow’s Distribution Channel." The study's focus is on raising the awareness of the potential monetization of P2P as a digital distribution platform.
According to its research, P2P traffic will grow almost 400% over the next 5 years, from a level of 1.6PB of Internet traffic per month in 2007 to almost 8PB per month by 2012. Current P2P traffic consumes some 44.0% of all Internet traffic. The figure is 33.6% in North America.
The study claims that although legal P2P traffic consumes a tiny share of the overall amount that it is expected to grow 10 times as fast as illegal P2P as content owners "increasingly see P2P as a cost effective way to distribute digital entertainment services and content."
Monetising P2p has been something on the table for years now and many failed efforts to compete with free are visible aound the web news archives, I suspect myself that whoever wrote this report had bit torrent or similar in mind when making thier seemingly extravagant claims.