Question: WNP-3 and WNP-5 were constructed by the agency formed in which year?

Context paragraphs:
WNP-1 and WNP-4: Washington Nuclear Project Nos. 1 and 4, abbreviated as WNP-1 and WNP-4 were two of the five nuclear power plants on which construction was started by the Washington Public Power Supply System (WPPSS) in order to meet projected electricity demand in the Pacific Northwest.  WNP-1, WNP-2 and WNP-3 were part of the original 1968 plan, with WNP-4 (a twin to WNP-1 and located at the same site) and WNP-5 (a twin to WNP-3, in similar fashion) added in the early 1970s.

Railway Express Agency Building: The Railway Express Agency Building was a historic building located at 1804 Western Avenue in Mattoon, Illinois.  The building was constructed in 1918 to serve as the Mattoon office of the Railway Express Agency.  The Railway Express Agency provided rail express shipping services to Mattoon's citizens, allowing them to ship money and packages along Mattoon's two major railways, the Illinois Central Railroad and Cleveland, Cincinnati, Chicago and St. Louis (Big Four).  The agency formed in 1917, when the federal government ordered that all existing express services consolidate into a single service; this measure ensured consistent shipping of goods during World War I.  The agency shipped goods to and from Mattoon until 1964, when the Big Four went bankrupt; the building served as a freight depot until 1971.

WNP-3 and WNP-5: Washington Nuclear Project Nos. 3 and 5, abbreviated as WNP-3 and WNP-5 (collectively known as the Satsop Nuclear Power Plant) were two of the five nuclear power plants on which construction was started by the Washington Public Power Supply System (WPPSS) in order to meet projected electricity demand in the Pacific Northwest.  WNP-1, WNP-2 and WNP-3 were part of the original 1968 plan, with WNP-4 (a twin to WNP-1 and located at the same site) and WNP-5 (a twin to WNP-3, in similar fashion) added in the early 1970s.

Energy Northwest: Energy Northwest (formerly Washington Public Power Supply System) is a United States public power joint operating agency formed by State law in 1957 to produce at-cost power for Northwest utilities.  Headquartered in Richland, Washington, the WPPSS became commonly known as "Whoops" due to over-commitment to nuclear power in the 1970s which brought about financial collapse and the second largest municipal bond default in U.S. history.  WPPSS was renamed Energy Northwest in November 1998.  Agency membership includes 28 public power utilities, including 23 of the state’s 24 public utility districts.

Road Safety Authority: The Road Safety Authority (Irish: "Údarás Um Shábháilteacht Ar Bhóithre" ) or RSA, is a state agency formed by the Irish Government to promote road safety.  The agency has devolved control of much of the work of the Department of Transport.

Anti-Corruption Commission Seychelles: The Anti-Corruption Commission Seychelles (abbreviated ACCS) is an independent Seychellois government agency formed under the Anti-Corruption Act 2016.  Formed in March 2016 after the National Assembly enacted the "Anti-Corruption Law No. 6 of 2016", the agency is charged with receiving complaints, investigating, detecting and preventing corruption-related practices in Seychelles.

Extraordinary State Commission: The Extraordinary State Commission was a Soviet government agency formed by the Council of People's Commissars on 2 November 1942, by a decree of the Presidium of the Supreme Soviet.  It was tasked with investigating World War II crimes against the Soviet Union and collecting documentation which would confirm material losses caused by Nazi Germany.  Its full ceremonial name was: ""Extraordinary State Commission for Ascertaining and Investigating Crimes Perpetrated by the German-Fascist Invaders and their Accomplices"" (Russian: Чрезвычайная Государственная Комиссия , ChGK).  The official aim of this agency included "punishing for the crimes of the German–fascist aggressors."  According to its own data, 32,000 organization staff took part in the work of ChGK and around 7,000,000 Soviet citizens had participated in the collection of materials and evidence.

Director General of the European Space Agency: The Director General of the European Space Agency is the highest-ranked official of the European Space Agency (ESA), a space agency formed by the collaboration of prominent European nations.

WorkCover Authority of New South Wales: The WorkCover Authority of New South Wales or WorkCover NSW is a New South Wales Government agency established in 1989.  The agency creates regulations to promote productive, healthy and safe workplaces for workers and employers in New South Wales.  The agency formed part of the Safety, Return to Work and Support Division established pursuant to the "Safety, Return to Work and Support Board Act, 2012" (NSW) .

Virginia State Board of Censors: The Virginia State Board of Censors was a government agency formed on August 1, 1922 for the purpose of reviewing and licensing films for approval to be screened in the state of Virginia.  During the agency's existence its members examined over 52,000 films, over 2,000 of which required edits before approval was given; and another 157 films were rejected entirely, of which only 38 won subsequent approval.  The board disbanded in 1968 following a series of U.S. Supreme Court rulings which overturned censorship statutes across the country.

Supporting paragraphs: WNP-3 and WNP-5 Energy Northwest
Answer: 1957