Quantcast (http://www.quantcast.com/) -- a company that measures what people are doing on the Internet -- recently began publishing stats on operating system browser share. Its latest stats show that Mac OS X's relative browser share has grown by 29.4% in the past year, while Windows lost 3.8%.

As noted by VentureBeat (http://venturebeat.com), January data from Quantacast shows that Windows accounted for 86.8% share of North American web consumption, Mac OS X accounted for 10.9%, and mobile browsers accounted for 1.3%. The iPhone/iPod touch combo accounted for more than 60% of mobile web consumption in January in North America.

"When it comes to operating system share, as estimated from the relative share of web consumption observed through Quantcast’s audience measurement services, Microsoft Windows leads the market by a long way, though is experiencing a gradual decline," Quantacast says. "Having held steady in the last three months of ‘09 (reflecting Windows 7 adoption) the decline started up again in January as a result of a strong holiday season for Apple."

As for Mac OS X, version 10.5 ("Leopard") still holds the largest percentage of the Apple market with 52.1%. Snow Leopard (10.6) has 27.3%, Mac OS X 10.4 has 17.2% and "other" tallies 3.4%.

"Apple's share of mobile web consumption in North American has declined from its Dec '08 peak, but given how much the market has grown, it's still gaining the largest absolute volume in the market every month," says Quantacast.