Does illegal file-sharing cut into CD sales?

Stan Liebowitz says yes, rebutting the well-known arguments of Koleman Strumpf, published in the Journal of Political Economy.  I would be happy to link to a response by Strumpf.  In the meantime, two notes: a) I suspect non-fair use CD burning is in any case the bigger issue, and b) significantly lower musical sales, and yes sales are falling, still can be welfare-improving.  The real consumption of music seems to be up.