Answer
STAFF
Sam Wierema
16-Apr-2012 13:24:48
According to our records we only have one record of you data (namely today, 16 April). When that happens the graph tries to correct this by calculating the average growth up until today. As you've noticed these are based on averages and can therefore be incorrect.
If you want to make sure your stats are up-to-date I would recommend pressing "Update stats now" at the top of your profile every once in a while.