AdDuplex publishes regular reports on the breakdown of devices (and countries / languages) active in the Windows Phone ecosystem based on data drawn from its advertising network (2,087 apps running AdDuplex SDK version 2.0 for the November report). The data represents a sampling of the active installed device base for Windows Phone, albeit one biased to those users who are more likely to install apps, as of November 22nd 2013.

Some of the key data points from this month's AdDuplex global report include:

• Windows Phone 8 devices represent 70.9% of devices detected by AdDuplex, up from 49.4% in June. 
• The Nokia Lumia 520 and 620 collectively represent just over 47% of active Windows Phone 8 devices.
• The Nokia Lumia 925 is now the 10th most common (2.3%) Windows Phone 8 device.
• The average app is used by two times as many users as a year ago.
• The Lumia 521 is the best selling Windows Phone device in the US (19.2%), moving ahead of the Lumia 822 (14.1%).

Globally the Nokia Lumia 520 is the most popular Windows Phone device by a considerable margin (23.2% of active Windows Phone device), it is followed by the Nokia Lumia 920 (9.2%), Nokia Lumia 620 (9.2%), Nokia Lumia 710 (7.7%), Nokia Lumia 800 (6.2%), Nokia Lumia 820 (5.6%), Nokia Lumia 720 (5.5%), Nokia Lumia 610 (4.0%), Nokia Lumia 900 (3.1%),  and the HTC 8X (3.1%). Other Windows Phone devices make up 23.2% of the active Windows Phone device base.

These statistics allow us to make a rough estimate of the number of active Windows Phone devices. Adding up known shipping totals, while allowing for the fact that some devices are no longer being actively used, we can conservatively estimate that there are around 40 million active Windows Phone devices. This would suggest Nokia has sold around 10 million Nokia Lumia 520 handsets and between 3 and 4 million Nokia Lumia 920 handsets.

Windows Phone 7 devices are gradually starting to fade (e.g. Lumia 710 reduced from 9.6% to 7.7% since July), while Windows Phone 8 devices are increasing their share (e.g. Lumia 720 increasing from 4.6% to 5.5% since July). As a result of the increased size of the active Windows Phone base month-to-month changes are relatively small and it take a little while for new devices to break into the top ten.

The global figures hide considerable regional variations. For example, in Israel the Lumia 820 is the post popular device (37.2%), followed by the Lumia 920 (28.5%), and the ATIV S (10.1%). This is a good example of how what phones an operator choose to range will have a big impact on the popularity of devices in a given market. Brazil provides an interesting contrast with the most popular device being the Lumia 710 (33.1%), followed by the Lumia 520 (24.7%), and the Lumia 800 (11.1%). This pattern of low end+older devices is repeated in a number of developing markets.

Nokia remains the leading device manufacturer for Windows Phone devices, with 89.2% of active Windows Phone 8 devices are made by the Finnish manufacturer. HTC remains in second place on 8.5%, Samsung in third with 1.8%, followed by Huawei in fourth place with 1.2%. As in the last few months there have been only minor changes from the preceding months, although Nokia does look set to break the 90% barrier in November.

Windows Phone 8 devices now represent 70.9% of all active Windows Phone devices, notably up from last month (67%). This trend should continue as more users reach the end of a two year phone life cycle pattern.

A full version of the AdDuplex report will be published on the company's blog tomorrow. 

Previous reports: July 2013, August 2013, and September 2013.