Top countries for Twitter users

Caution - see note 1 below
The top 10 counties by percent of total Twitter users.  I.e. 50% of Twitter users are in the US.

COUNTRY    % OF USERS
United States    50.99
United Kingdom    17.09
Australia            4.09
Brazil            3.44
Canada            2.92
India                    2.87
France            1.76
Indonesia            1.43
Iran                    0.88
Ireland            0.85
Source:  Beevolve, October 2012
Note 1 - These are unofficial stats.  If you take Twitter's official statment that there are approx 140m active accounts, then there are approximately 70m Twitter users in the US, and over 20m in the UK.  Hmmm - UK figure looks too high (Population is 60m)
Note 2 - Lots of other stats in the full article