From Microsoft's Q4 earnings conference call (full transcript here):
We estimate PC market growth during the quarter at 14-15%, which is stronger than we expected 3 months ago. A very strong holiday sales season resulted in consumer PC shipment growth outpacing business shipments for the third consecutive quarter. From a form factor perspective, growth in notebook PC shipments continues to outpace desktops.
PC unit demand was broad-based regionally with double-digit growth rates in all geographies, except for North America and Japan and emerging market growth rates continue to significantly outpace mature markets.