Kathy Kupper, a spokesperson for National Park Service, said in an email to ABC15 that the National Park Service was returning to fewer fee-free days because the Centennial had passed and "the nation is recovering from the recession."
Between 2003 and 2008, NPS had two fee-free days, Kupper said. In 2009, the years following the recession, that number was increased to "encourage visitation by citizens with financial constraints."
In 2016, the number was increased to 16 days to coincide with NPS' Centennial.
Kupper said fewer fee-free days would also bring in more money to improve facilities, take care of deferred maintenance issues and better the parks.
In October, U.S. Secretary of the Interior Ryan Zinke and the National Park Service proposed to increase daily entrance fees during peak months at 17 national parks, including Grand Canyon National Park in Arizona, and Arches and Bryce national parks in Utah, to raise money to fix roads, bathrooms and aging infrastructure.
The proposal is in the public-comment phase which runs through Dec. 22. Zinke said the proposal would raise an additional $70 million.
More than 331 million people visited national parks last year and spent more than $18.4 billion, according to the National Park Service.