If you're talking about products I own and use on a daily basis, including hardware and software, I'm in the very high 90%s. My home computer is a Toshiba laptop running Windows 8.1 and Office 2010, although I do have some non-Microsoft apps on it. I have a Surface RT that I use daily which is all Microsoft, and my smartphone is a Lumia 920 (although I do own an iPhone 4S because I support iPhone at work and I like to keep abreast of iOS updates). I also have an Xbox 360 with a couple of games that I don't ever play, heh, and my car is a Ford which has Microsoft Sync.
At work my desktop is an HP something-or-other running Windows 8.1 and Office 2010. The only non-Microsoft apps I have on this machine are Komodo Edit and Private Shell. We're pretty much an all-Microsoft shop with Windows Servers, Exchange Server 2010 and SharePoint 2010, although I do run a Linux server for our website (thus... Private Shell for SSH access).
Pretty much I think that puts me in the 98-99% range.