CHART OF THE DAY: Microsoft's Big Problem In One Chart

Microsoft's stock was clobbered today, falling 11.4%.

The most obvious reason for the decline: The collapse of the PC industry has finally hit Microsoft's earnings.

Windows operating income fell by over 50% on a year-over-year basis. It took a $900 million charge for inventory of its Surface RT tablet. Its CFO admitted that it's going to take a while for tablet sales to offset the decline of the PC.

Few charts illustrate what's happening to the PC market, and thus, what's happening to Microsoft, better than this one from Horace Dediu, independent analyst/blogger at Asymco.

Microsoft's monopoly over our computing is dead.

Combined iOS/Android unit sales are outpacing PC sales 2.6 to 1.