Microsoft has been tight-lipped about shipping numbers for its Surface tablet, but for the first time the company is sharing just how much money the devices have brought in so far: $853 million. That's less than both their write-down for unsold Surface RT units ($900 million) and the advertising costs associated with the tablet alongside Windows 8 ($898 million). The figure covers sales for both Surface tablets, the Surface RT and Surface Pro, for a period from their launch in October 2012 to the end of June this year.

For most companies, $853 million is a significant amount. But when it comes to Microsoft it's worth noting that the Windows division as a whole (including Surface sales) brought in $19.2 billion.

Additionally, the Server and Tools brought $20.3 billion, the Business division which accounts for Office brought $24.7 billion, Entertainment and Devices including Xbox and Windows Phone brought $10.1 billion, and even their Online Services division that reported a loss managed $3.2 billion in revenue.

Overall, out of the total revenue of $77.8 billion for the year, sales of Surface tablets accounted for just 1% of total revenue. Combined with the significant write-down, the fact CEO Steve Ballmer claimed the company built too many Surface RT units, and that the Surface pulled in less revenue than was spent on advertising, it's safe to say Microsoft's first foray into producing tablets was a flop.

That said, Microsoft appears to be developing a successor to the Surface RT, likely with a Qualcomm Snapdragon 800 SoC inside and running Windows RT 8.1 out of the box. It would make sense for Microsoft to release this tablet towards the end of the year, after the current model has been on sale for a year, but neither the tablet or its release date have been confirmed.