The indefatigable Horace Dediu points out on Asymco.com that although Apple’s (AAPL) iOS and Google’s (GOOG) Android are less than two years old as platforms, together they have captured 50.2% of what he calls “the most competitive market technology market on the planet.”

Below: The same data graphed as market share.

Also on Fortune.com:

• Apple is still sucking most of the profit out of the mobile phone business
• The ebb and flow of Apple’s cash
• Chart: Where Apple makes its money

[Follow Philip Elmer-DeWitt on Twitter @philiped]