The decade-old XP closed July with 49.8%, a 1.3-percentage point drop from June, Net Applications said today. Although XP still powers a majority of Windows machines, July's decline means it has lost its majority status among all operating systems.

Other metrics firms marked an earlier fall for XP. The Irish company StatCounter, for instance, said that the OS slipped under 50% last January. But unlike that rival, Net Applications' methodology weights its data by country to more accurately reflect use in countries like China, which produces relatively little data for Western measurements but has a huge pool of PC users.