industry, including oil, gas, trona, and coal, provided $1.3 billion in property taxes from 2006 mineral production. As of 2017, Wyoming receives more federal tax dollars as a percentage of state general revenue than any state except Montana. As of 2016, Wyoming does not require the beneficial owners of LLCs to be disclosed in the filing, which creates an opportunity for a tax haven, according to Clark Stith of Clark Stith & Associates. Transportation Wyoming's largest airport is Jackson Hole Airport, with more than 500 employees. Three interstate highways and 13 U.S. highways pass through Wyoming. The Wyoming state highway system also serves the state. Interstate 25 enters Wyoming south of Cheyenne and runs north, intersecting Interstate 80 immediately west of Cheyenne. It passes through Casper and ends at Interstate 90, near Buffalo. Interstate 80 crosses the Utah border west of Evanston and runs east through the southern third of the state, passing through Cheyenne before entering Nebraska near Pine Bluffs. Interstate 90 comes into Wyoming near Parkman and cuts through the northeastern part of the state. It serves Gillette and enters South Dakota east of Sundance. U.S. Routes 14, 16, and the eastern section of U.S. 20 have their western terminus at the eastern entrance to Yellowstone National Park and pass through Cody. U.S. 14 runs eastward before joining I-90 at Gillette. U.S. 14 then follows I-90 to the South Dakota border. U.S. 16 and 20 split off of U.S. 14 at Greybull and U.S. 16 turns east at Worland while U.S. 20 continues south Shoshoni. U.S. Route 287 runs from Fort Collins, Colorado, to Laramie, Wyoming, through a pass between the Laramie Mountains and the Medicine Bow Mountains, then merges with US 30 and I-80 until it reaches Rawlins, where it continues north, passing Lander. Outside of Moran, U.S. 287 is part of a large interchange with U.S. Highways 26, 191, and 89, before continuing north to Yellowstone's southern entrance. U.S. 287 continues north of Yellowstone, but the park separates the two sections. Other U.S. highways that pass through Wyoming are 18, 26, 30, 85, 87, 89, 189, 191, 212, and 287. Wyoming is one of only two states (the other is South Dakota) in the 48 contiguous states not served by Amtrak. It was once served by Amtrak's San Francisco Zephyr and Pioneer lines. While no passenger trains roll through Wyoming today, intercity buses continue to connect