Well, it's official: Fully 90 percent of all Windows Phone handsets in use are now made by Nokia. And the most frequently-used Windows Phone handset, the Lumia 520, is more popular than ever. The news comes courtesy of the latest handset usage data from AdDuplex.

As you may remember, AdDuplex bills itself as the largest cross-promotion network for Windows Phone and Windows 8 apps, empowering developers and publishers to promote their apps for free by helping each other. And each month it provides a tantalizing glimpse at which Windows Phone (and Windows) devices people are actually using.

Some trends from this month's report include:

Lumia 520 continues to rule. The little phone that could now represents 26.5 percent of all Windows Phones in use, up from 23.2 percent last month. But its success is even bigger than those numbers suggest. The gap between this phone and the number two phone, the Lumia 920, is now 17.7 percentage points. Last month it was just 14 percent points. And if you look at just Windows Phone 8 devices, the Lumia 520 owns 35.3 percent of the market. Over one out of every three Windows Phone 8 handsets in use right now is a Lumia 520. Amazing.

Lumia 520 + 521. Since they are basically the same phone, perhaps we should look at the Lumia 520 and 521 together. When we do, the gap between these devices and the rest of the market grows even further, as you'd expect: Together they represent 29.9 percent (let's call it an even 30 percent) of all Windows Phones in use, or 39.9 percent (or an even 40 percent) of all Windows Phone 8 handsets in use. In the United States, these two devices combine for exactly 30 percent of the market as well. That's almost three times the usage share of the number two phone here, the Lumia 822.

Nokia has 90 percent usage share. It came close last month, but this month it's official: Nokia now has exactly 90 percent usage share, compared to 7 percent for HTC, 1.8 percent for Samsung and 1.3 percent for Huawei.

Windows Phone 8 hits 75 percent. Handsets running Windows Phone 8 now constitute 75.3 percent of all Windows Phone handsets in use. (In the US, it's 86 percent.)

AT&T is number one again. After a strong year by Verizon, AT&T has regained its footing and is now the number one wireless carrier for Windows Phone users in the US with 31.7 percent usage share. Verizon settled in at 27.5 percent with T-Mobile a strong 20.6 percent thanks to the Lumia 521.

Lumia 1520. Finally, after the week showing of the Lumia 1020 this year—yes, still my favorite smart phone by far, you may be wondering how the new Lumia 1520 is faring. It just came out, but I don't expect things to go so well, and its 19th place finish (in a field of 21 Windows Phone 8 handsets) bears this out. Only the Samsung ATIV S Neo and Huawei W2 (both with limited availability) do more poorly in this month's stats.