New research confirms what we’ve known for a while now: Nokia is really the only company putting effort into developing and marketing Windows Phone devices. AdDuplex, a cross-promotion network that tracks usage on Windows Phone devices, has found that Nokia handsets account for 88% of all Windows Phone devices in use as well as 9 out of the top 10 most used Windows Phone devices. Nokia’s budget Lumia 520 is the most used Windows Phone device with a 21.3% share, followed by the high-end Lumia 920 at 9.3% and the Lumia 620 at 9.1%. The only non-Nokia device to crack the top 10 for Windows Phone usage was the HTC 8X, which had just a 3.2% share. From this perspective, it’s easy to see why Microsoft was so eager to buy Nokia’s handset division: If it’s going to be the only major supporter of the Windows Phone platform, it might as well work directly with Microsoft’s own software engineers.