Having other books to compare to would add another layer of understanding, but to say the graph says nothing is obviously wrong. There is a discernible pattern which repeats itself along the entire scope of the timeline.
Since issue number 7, sales have dropped by an average of about 1000 per month.
And for comparison to Gail's run...
07/2008: Wonder Woman #22 -- 36,514
That means book sales are down by about 500 issues - Rob says digital sales are over 2000 so that means it is still ahead, but the difference is fractional...in the order of 5%.