Google is not exactly a friend to Windows Phone, but they do have some nifty tools, including Google Trends, which in the above video shows the spread in interest in Windows Phone worldwide as indicated by search volume.
The list of countries where Windows Phone is strong correlated pretty much with what we expect from Microsoft statements:
Finland is predictably the peak, and India, Italy, Germany, the Czech Republic, Poland and Mexico are all countries we have head have a significant number of Windows Phone users.
The video also shows that interest fluctuates in time, sometimes waxing and sometimes waning, likely with the introduction of new phones into the various markets.
Overall however Windows Phone is getting solidly established in Northern and Eastern Europe and Europe in general, and Russia, India and South America, all previously strong Nokia markets.
See an interactive map with a map of the whole world after the break, to see where your country stands.