Chromebooks (which use linux) accounted for over 5% of laptop shipments in Q3 of last year. They also grew at an astounding rate of 67% quarter over quarter. I have not seen data for Q4 of last year yet, but considering the chromebooks' growth rates it will probably be even higher.

So, no desktop linux market share is not non-existent and it is definitely not shrinking.

http://www.zdnet.com/article/chromebook-shipments-leap-by-67...