Average attendence at the top 50 is between half a million and 1.5 million people, according to Amusement Business.
Karen Oertley, publisher and editor in chief of Amusement Business, said new attractions were critical to getting visitors through the gates.
Amusement Business prospered for a few decades, but was struggling by the beginning of the 21st century.
This year, according to Amusement Business, which tracks the $8 billion industry, is a record one for roller coaster construction, with nearly 80 being built worldwide.
The 15 most popular amusement parks had 93 million visitors last year, Amusement Business, a trade paper, reported.
The Six Flags park here, for instance, has seen attendance go from 3.2 million in 1990 to just 3.4 million last year, according to Amusement Business.
It also owns Backstage, Amusement Business, Interior Design and several others.
Amusement Business, the industry magazine, has estimated that Disney's 1990 attendance fell 5 percent, to 28.4 million, from about 29.9 million a year earlier.
The increase reflects the national trend at concert arenas, according to Amusement Business, a trade newspaper.
Universal Studios in Orlando had 7.4 million visitors last year, according to Amusement Business, a trade magazine.