Bluebulb Projects' The Measure of Things presents:
68 is about half the number of Union Stations in the United States.
In other words, it's 0.5040 times the count of Union Stations in the United States, and the count of Union Stations in the United States is 1.980 times that amount.
(a.k.a. Union Terminal; a.k.a. Joint Station; a.k.a. Union Depot) (2016 figures) Typically shared between multiple railroad companies and stations, there are about 135 "Union Stations" in the United States. Of these, the busiest station is Chicago Union Station, which handles 120,000 passengers each year.