Here's a news item from the Associated Press:
YELLOWSTONE NATIONAL PARK, Wyo. (AP) — Yellowstone National Park has recorded its third busiest visitation during the month of May as the park began opening up for the busy summer tourist season.
The National Park Service says the park recorded 434,385 visits last month. The total is 2.8% less than May 2018, which was the busiest May on record.
So far in 2019, Yellowstone has counted more than 576,700 visits, which is up 1% from the same five-month period last year.
The park in Wyoming, Montana and Idaho typically sees its most visitors during the summer months.