Article: In November 2005, the Polish government opened its Warsaw Treaty archives to the Institute of National Remembrance, who published some 1,300 declassified documents in January 2006. Yet the Polish government reserved publication of 100 documents, pending their military declassification. Eventually, 30 of the reserved 100 documents were published; 70 remained secret, and unpublished. Among the documents published is the Warsaw Treaty's nuclear war plan, Seven Days to the River Rhine – a short, swift counter-attack capturing Austria, Denmark, Germany and Netherlands east of River Rhine, using nuclear weapons, in self-defense, after a NATO first strike. The plan originated as a 1979 field training exercise war game, and metamorphosed into official Warsaw Treaty battle doctrine, until the late 1980s – which is why the People's Republic of Poland was a nuclear weapons base, first, to 178, then, to 250 tactical-range rockets. Doctrinally, as a Soviet-style (offensive) battle plan, Seven Days to the River Rhine gave commanders few defensive-war strategies for fighting NATO in Warsaw Treaty territory.[citation needed]

Question: In which year did Poland declassify most of its Warsaw Pact-era archives?
2005