Net Applications’ “Market Share” has posted their operating system market share statistics for September 2007 showing Apple Macintosh share at 6.61% (3.38% for non-Intel-powered Macs and 3.23% for Intel-powered Macs).

In September 2006, Net Application’s reported Mac share was 4.72%, so Apple Mac share has risen 1.89 percentage points or 40% year-over-year.

Net Applications’ “Market Share” stats September 2006 – September 2007:
(Month: non-Intel Macs + Intel-powered Macs = total Mac market share)
09/06: 3.88% + 0.84% = 4.72%
10/06: 4.09% + 1.12% = 5.21%
11/06: 4.10% + 1.29% = 5.39%
12/06: 4.15% + 1.52% = 5.67%
01/07: 4.34% + 1.88% = 6.22%
02/07: 4.29% + 2.09% = 6.38%
03/07: 3.94% + 2.14% = 6.08%
04/07: 3.89% + 2.32% = 6.21%
05/07: 3.95% + 2.51% = 6.46%
06/07: 3.52% + 2.48% = 6.00%
07/07: 3.36% + 2.61% = 5.97%
08/07: 3.33% + 2.82% = 6.15%
09/07: 3.38% + 3.23% = 6.61%

Net Applications’ “Market Share” uses a unique methodology for collecting this data. The company collects data from the browsers of site visitors to their exclusive on demand network of small to medium enterprise live stats customers. The sample size for these sites is more than 40,000 urls. The information published is an aggregate of the data from this network of hosted website statistics. The site unique visitor and referral information is summarized on a monthly basis. The websites in ther population represent dozens of countries in regions including North America, South America, Western Europe, Australia / Pacific Rim and Parts of Asia. It is more a measure of installed base than of market share.

Reasons for Mac gains run the gamut from superior security vs. Windows, Apple’s growing retail store network, the iPod Halo Effect, award-winning design, Mac OS X, Mac-only applications such as iLife, ease-of-use, the Mac’s unique ability to run Mac OS X, Linux and Windows concurrently, word-of-mouth, excellent reviews, and more.

Net Applications’ Operating System “Market Share” for September 2007:
79.32% – Windows XP
7.38% – Windows Vista
6.61% – Mac OS X (combined PPC + Intel)
3.32% – Windows 2000
0.89% – Windows 98
0.81% – Linux
0.61% – Windows NT
0.49% – Windows ME
0.13% – Pike v7.6 release 92
0.12% – Nintendo Wii
0.10% – Unknown
0.07% – iPhone (0.04% in July, 0.05% in August)
0.06% – Windows CE
0.03% – Series60

Net Applications’ Operating System “Market Share” stats can be found here.