Apple's share of the operating system market increased in January by three-tenths of a percent from the previous month, while Microsoft lost more than four-tenths of a percent, a Web tracking firm said Monday.

Last month, Apple's Mac OS X was in 9.93% of the machines accessing the Web, while Microsoft's Windows dipped to 88.26%, according to Net Applications. While the tracking firm's numbers aren't bulletproof, they are an indicator of OS use.

Apple's market share has risen month to month in seven of the last 11 months. In March 2008, the Mac OS X had a share of 7.48% and in December it was 9.63%. Microsoft, on the other hand, has seen its share drop in seven months since March, when Windows had a 91.57% share. In December, Windows had an 88.68% share.

The latest numbers from Net Applications followed almost two weeks after Microsoft reported an 11% drop in net income and an anemic 1.6% rise in revenue in its most recent fiscal quarter as a result of a decline in sales of Windows and a weak global economy. Apple, on the other hand, reported the same week a 9% increase in sales of Macintosh computers during its most recent quarter.

All other operating systems in Net Applications' chart had less than 1% of the market. Linux had the third-largest share in January with 0.83%, which was up more than two-tenths of a percent from March 2008, but down from 0.85% in December.

In the browser market, Microsoft's Internet Explorer saw a month-to-month dip in January of sixth-tenths of a percent to 67.55%, according to Net Applications. Mozilla's Firefox, on the other hand, rose nearly two-tenths of a percent to 21.53%. In March 2008, IE and Firefox had a share of 74.8% and 17.83%, respectively.

Apple's Safari has seen a decent gain since March 2008, rising to 8.29% from 5.82%. In December, Safari had a 7.93% share.

Google's Chrome browser, which broke the 1% mark in December, rose to 1.12% in January from 1.04%.