I'm taking a shot in the dark here - but I'll bet there's a large account that's powering down on that date that's swinging the average. It might even be someone still powering down on the old 102 (?) week powerdown schedule?

You're right though, that's interesting. I wasn't looking for this data for trend patterns (thus no chart), it was meant to be more of a lookup table for those who are dealing with EOY tax processes.