Don't want to link to CNN but they have the article if you google it.
With the new kudos for W7, we're now looking at 42.76% for W7 and 42.42% for XP and including Vista, 92% market share for Microsoft (4.83% for the Mac). These are total market; not Logos as has already been discussed.
But the significance for planning purposes is the '11 years'. Assuming Microsoft doesn't something nutty, good old Libronix (on W7-32) and of course Logos4 are going be nice and comfy for a long while.