Switched 4 PC's in our office to Bing homepage last August, 11 months ago. We still check Google results when we aren't satisfied, but that trend has slimmed to almost none now.
If I had to estimate, were 95-98% Bing now. The ONLY thing we really use Google for is gmail, which is also the ONLY thing we use the Chrome Browser for. All work is done in FF, behind the GoogleSharing add-in to work behind a proxy.