[web2py] How to implement http_user_agents statistics?

[thstart]

I am recording http_user_agents info like this:
 *value:* [u'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; 
Trident/5.0)', u'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.7 
(KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7', u'Mozilla/4.0 
(compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 
2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; 
InfoPath.3; .NET4.0C; BRI/2)'] 
In order to optimize the app according most used devices.
How is the best way to analyze this info and make a statistics?