Answer
STAFF
Sam Wierema
02-Sep-2011 07:27:32
According to our records there is a gap in your statistics between May and August. Since there haven't been a lot of tweets in that time span our algorithm calculated that they were done in the beginning, distributing them unevenly over the graph (which is seen in the 6 month graph).
As we're once again tracking your stats they should be updated whenever you send out a tweet.