Someone suggested adding in the Halloween and Christmas Party dates to these. It's a good point.
There were 24 Halloween Party dates in 2009: September 4, 11, 15, 18, 22, 25, 29; October 1, 2, 6, 8, 9, 12, 13, 15, 18, 20, 22, 23, 25, 27, 29, 31; November 1.
There were 18 Christmas Party dates in 2009: November 10,12,13,17,19,20,29; December 1,3,4,6,8.10,11,13,15,17,18.
This was 2009, in the depths of the Great Recession. But for kicks, let's assume that all 42 dates sold out at 25,000 tickets each. That would bring the upper end of the MK attendance estimate to 16.2 million, about 800K short of TEA's claimed attendance of 16.972MM.
The lower end of the estimate would be around 15.2MM, around 1.7MM short.
What else is this estimate missing?