I really don't know how they come up with these estimates.
It's estimated that the iPad will sell 40 million units this year. Judging by the relative sizes of the graph, other mobile tablets will sell around 18 million units this year and PC tablets will sell around 3.5 million units.<p>With the year already 17% over, and only two real competitors on the market (Xoom and Galaxy Tab), I fail to see how 18 million Android tablets are going to suddenly fly off the shelf. I don't even think and Android Tablet makers are planning for anywhere near that amount of uptake.