About 30 percent of all workers were employed in water transportation services. About one half worked in inland water transportation—primarily the Mississippi River system—while the other half were employed in water transportation on the deep seas, along the coasts, and on the Great Lakes. About another 28 percent worked in establishments related to port and harbor operations, marine cargo handling, or navigational services to shipping. The Federal government employed approximately 5 percent of all water transportation workers, most of whom worked on supply ships and are Civilian Mariners of the Department Navy's Military Sealift Command.