Maybe I was being a bit obtuse. But the data under scrutiny here formed a key part of the famous and influential Hockey Stick graph, which would not have garnered so much attention - or looked so good - if it did nor have a dramatic uplift at the end. This article suggests that the uplift was a consequence of cherry picking of data.
If only I could make my website's traffic graph look like that. Actually, with a bit of statistical abuse, maybe I can!