Nokia Lumia 920 emerges as the most popular Windows Phone 8 handset

ACCORDING TO LATEST SURVEY BT ADDUPLEX.
Most popular Windows Phone handsets ARE: Nokia Lumia 710 (24 percent)
Nokia Lumia 800 (18 percent)
Nokia Lumia 610 (17 percent)
Nokia Lumia 900 (7 percent)
HTC Radar (4 percent). 
Yes, these are all Windows Phone 7.x devices

Windows Phone OS versions. Windows Phone 7.5 dominates, of course, with 94.8 percent of the overall market, compared to a higher than expected 5.2 percent for Windows Phone 8.

Countries: The biggest Windows Phone market is the US (14 percent), followed by China (13 percent), India (12 percent), Mexico, Russia, and Italy (6 percent each), and the UK (4 percent). AdDuplex notes that growth in Mexico, Brazil and Finland is notable.