Given the vast differences in smart phone use (such as iOS web use stats versus android), how meaningful is this? If a smart phone is being used as a dumb phone (feature phone in marketing speak), it seems a touch meaningless to use stats like these to show that Microsoft is declining. It's not that I'm saying Microsoft's relevance is declining, it's that stays like these may not mean anything. Taken a step further, surely a low cost phone being used as a dumb phone is actually a point against Google, due to development costs and no monetary gain for Google.
It's a bit weird that in 2005 Other and Apple leap to 50% of the market, years before Android and iPhones and a year before Intel chips in Apple computers. Linux was also long and well established in servers by then if that's what it represents.
It's especially weird Goldman Sachs explicitly declined explaining what happened.