As of January 2017, U.S. Government-owned merchant vessels from the National Defense Reserve Fleet have supported emergency shipping requirements in 10 wars and crises. During the Korean War, 540 vessels were activated to support military forces. A worldwide tonnage shortfall from 1951 to 1953 required over 600 ship activations to lift coal to Northern Europe and grain to India. The Department of Agriculture required 698 activated ships to store grain from 1955 through 1964. After the Suez Canal Crisis in 1956, the NDRF activated 223 cargo ships and 29 tankers. During the Berlin Wall Crisis of 1961, 18 NDRF vessels were activated, remaining in service until 1970. The Vietnam War required the activation of 172 vessels.