In January I noted that there were more iPads sold by Apple than PCs from HP, the largest PC vendor in the fourth quarter. Including all tablets, this is the distribution of market shares by units shipped.
Note the different color palettes for Windows and non-Windows.
By the metric of tablets+PC’s Apple appears to be the leading vendor. However, if we consider only the Mac, Apple is still well behind. The historic unit volumes of the two is shown below: