I think the increase was pretty massive. The drop from '15-'16 was around 1%. The increase from '16-'17 was closer to 5%, iirc. I'll edit with the wikipedia link & numbers.
https://en.wikipedia.org/wiki/List_of_amusement_park_rankings
2015 2016 2017
MK 20,492,000 20,395,000 20,450,000
EP 11,798,000 11,712,000 12,200,000
HS 10,828,000 10,776,000 10,722,000
AK 10,922,000 10,844,000 12,500,000
54,040,000 53,727,000 55,872,000
Up 3.3% from 2015,
probably close to exactly 4% from 2016 (
lazy & didn't add up). Should be noted, almost all the gain was from AK & Epcot. MK & HS didn't rebound. HS suffered due to closures, especially as
@Minnesota disney fan mentioned the Osborne lights, but also the general idea that it had become a 'half day' park. MK seems to be bouncing around its limits, which will definitely be tested in 2021. Was down 0.6% in 2016.