Established in 2015, The Northwest Seaport Alliance (NWSA) is a marine cargo operating partnership between the Ports of Seattle and Tacoma. The Alliance manages the majority of marine cargo facilities across both ports, including all containerized cargo operations, breakbulk, automobiles, project/heavy-lift cargoes and some bulk operations. The North Harbor, or the Port of Seattle, has five container terminals. A variety of properties provide supporting activities to its containerized cargo terminals. The BNSF Seattle International Gateway Yard and the Union Pacific Cargo Yard provide essential rail services for its containerized cargo activities. Terminal 106, south of Harbor Island and on the east side of the Duwamish River, is used as a container support yard. Terminal 107, on the west side of the Duwamish River, and Terminal 108, on the east side of the Duwamish River, offer moorage for barges. The South Harbor, or the Port of Tacoma, has six container terminals, as well as Blair Terminal, where automobiles are offloaded. East Blair 1 provides services for roll-on/roll-off (RoRo) vessels and the West Hylebos Log Yard provides services for log exports. Terminal 7, on the south end of East Sitcum Terminal, also provides automobile and RoRo services. While full containers represent more than 75% of all TEUs handled by the NWSA, empty containers are also an important part of its containerized cargo activities. Both full and empty containers are loaded and off-loaded from vessels, requiring the expertise of a wide range of industries and occupations, including terminal operators, longshore workers, truckers and more. Leading import commodities included machinery, furniture, rubber plastics, base metals and transport equipment. Leading export commodities included oil seeds, prepared foodstuffs, wood pulp and wood products. In 2017, the vessel value of containerized cargo handled by the NWSA was nearly $75.3 billion. Imports represented 77% of total vessel value, or $58.3 billion, while exports totaled nearly $17.0 billion. Among the leading commodities in 2017 were machinery, transportation equipment, base metals, toys and apparel. The countries with the most containerized cargo moving through the NWSA included China, Japan, South Korea, Taiwan, Vietnam and Hong Kong, which together represented more than 80% of all TEUs traveling through the NWSA.