We’ve improved the accuracy of the Akismet stats feature that was introduced in Akismet 2.2.1. You might notice a slight change in the total spam, comments and accuracy figures reported at the top of your stats page, and the percentages shown in the pie chart. The Historical Stats figures and time graphs are unaffected – these were correct all along.
There’s no plugin upgrade required.
Our overall spam statistics remain unchanged, and Akismet is as accurate as ever.
Akismet 
does it measure spam stats OR visitor stats ?
I get so much spam that it wasted so much of my time, thanks to Akismet. I am so grateful.
meethere, the Akismet stats feature only measures comment stats – both spam and legitimate comments. Visitor stats are handled by the WordPress stats feature.
spam stats of course!