It's unlikely that most Corporates/SMEs will move to Win8 in the next couple of years - they have all just moved/are moving to Win7, and the effort involved in migrating and integrating hundreds, if not thousands, of applications (including complex Line of Business and ERP systems) on hundreds, if not thousands ,of desktops, isn't something people want to do more than every five years or so....
According to Tiz's link, Win8 is growing at 0.5% per month, or 6% per year - so it should take around 16 years or so....
