Well, SD I suppose, yes. I'm basically just saying that the graph is a bunch of baloney. Same reason I don't give an "average mileage" of hybrids in the database. It's a meaningless statistic.
That's why "average" isn't as meaningful as median. The median was probably unchanged over nearly all those years, but because Honda came out with the 255hp Accord hybrid, it brought the "average" way up.
Median is useless with such a small sample size, though. A 5, 10, 15 and 200 horsepower car set has a median of 15. That isn't representative. The fact that they "averaged' in any way and graphed the "data" is the baloney I'm talking about. It's extremely misleading.