IDC have some new stats and forecasts on tablet shipments. IDC have actually increased their forecast for tablet sales due to greater than expected demand for particularly sub-8" tablets. Of particular note between 2011 and 2012, Android slightly eroded iOS market share and Windows tablets gained insignificant market share despite the introduction of Windows 8.
An observation I have is that most Android projects coming my way seem to be predominantly smartphone rather than tablet-based. Maybe innovators/entrepreneurs are missing the Android tablet app opportunity?