How to count the number of documents filtered by TV?

To make some statistic I need to count the number of documents containing spesific data in TVs. Exsample:

Lets say I have a TV called color with values red, blue, green, white, yellow. And I want to count the number of documents containing blue in the TV named color and output that number in a list.

How can I do that? 

perhaps this would be useful:

http://modxcms.com/forums/index.php/topic,32608.msg198559.html#msg198559

Thanks. I missed that one, and I reed the forums every day.