AECOM's Themed Entertainment Index for 2018 is now available: https://www.aecom.com/content/wp-content/uploads/2019/05/Theme-Index-Museum-Index-2018-2.pdf
(^Houston Museum of Natural Science attendance showed meager growth, but still dropped to 10th place amongst museums in the US, and Schlitterbahn Galveston Island remains a decently-attended regional attraction. Worldwide Observation Experiences have been added to this year's report.)