Microsoft higher-ups might not exactly be shaking in their boots upon hearing this news, but market research firm Net Applications has just released new information that puts the Windows OS market share at its lowest point in 15 years. That low point – 89.62%. Yes, Microsoft still holds the overwhelming lion’s share of the computer OS market and that most definitely won’t be changing any time soon. Since 2004 when Net Applications began OS market share data however, Microsoft’s market share has been steadily declining. Windows reportedly had an astounding 96.4% of the OS market in October of 2004 when Net Applications’ first report on the subject was issued. In other words, Microsoft is losing an average of 1.7% of the market each year, a trend that it certainly hopes to reverse with its recent advertising campaign and eventually with the release of Windows 7. An interesting related note – Vista currently holds approximately 20.45%, up 2.12% over the past three months. Microsoft’s recent ad campaigns have been going strong during that period so this may appear to be a small victory until XP’s market share loss of 2.36% over the same period is considered. As for Microsoft’s largest competitor, Apple’s market share now sits at 8.87% up from 6.80% in November of last year and 3.2% in November of 2004 when the first Net Applications OS report was published.