I would have assumed it's declining in terms of market share (driven down by tablets/Mac/Linux) but there's a surprisingly large absolute drop coming as well:

"Researchers IDC and Gartner Inc. said PC shipments in the third quarter fell more than 8% from a year earlier, the steepest drop since at least 2001." ( http://online.wsj.com/article/SB1000087239639044465780457804... )