The VMware entrance in the Apple market in August 2007 doesn't seem to have damaged Parallels business too much.
The company in fact reports over one million Parallels Desktops copies sold worldwide.

Unfortunately Parallels doesn't reveal how its sales trend is these days, and in which countries the product is more popular than VMware Fusion.

In any case the market may be big enough for both: the third big, Microsoft, decided to discontinue its Virtual PC for Mac in August 2006. Who knows how many executives regret for the choice after seeing the Parallels results?