The latest - though preliminary - tablet shipment figures from market intelligence firm Strategy Analytics show Apple continued to lose its share of the market during the first quarter of 2015.
The iPad family slipped from 29% to 24% by volume in 12 months as Android's share rose from 66% to 69% and Windows' from 5% to 7%.
But in terms of the number of tablets shipped, Microsoft's operating system was the only winner, albeit one coming off a low base.
Windows' improvement from 3.1 to 3.4 million tablets was ascribed by Strategy Analytics tablet and touchscreen strategies service director Peter King to better than expected sales of the Surface Pro 3 plus various vendors offering low-cost sub-9in tablets in response to Microsoft's licensing changes.
"Apple, Google, and Microsoft are all eager to show enterprise customers that Tablets can perform in key verticals and as PC replacements in the office," said tablet and touchscreen strategies senior analyst Eric Smith.
"The Apple-IBM MobileFirst partnership, expanded access to Microsoft Office on Tablets, and better productivity and security functionality via Android for Work and Samsung's Knox solution are all crucial ecosystem enhancements to making the Tablet more attractive."