The big thing about TP is they drastically changed their crowd calendars in 2015 because the crowds were increasing. They tweaked that in 2017 to reflect the continued uptick in crowds. So now if you are comparing 2017-2018 you are comparing apples to apples. If you compare 2015,16,17 and 18 you are closer but not exactly apples to apples. However if you look at anything before 2015 you are looking at pomegranates. A crowd level of 1 in 2018 is equal to a crowd level of 9-10 with the 2011 numbers TP used through 2014. So yes you can't compare every year but you can compare the last 2-3 pretty well to see trends. Crowds have gone done in June and July over the last 2 years but have gone up the rest of the year using TP's crowd calendars with the past crowd levels. So looking at those numbers is why I am skeptical about how low the predictions are for Nov and Dec this year. I am still hoping they are correct and the levels will be as low as they say but I am taking a wait and see attitude. Also they can't predict what Disney will do with ride capacity which throws their numbers way off. Disney has already cut ride times in AK for Nov and Dec and I wonder how that will affect the lines on other rides. They changed one of my FP's because of this and did affect my plan for the day I am at AK.