Question: What Report reported a 40% decrease in the number of armed conflicts being waged around the world once the state of geopolitical tension after World War II between powers in the Eastern Bloc and powers in the Western Bloc came to a close?
Sentence (from "Cold War"): Historians do not fully agree on the dates, but a common timeframe is the period between 1947, the year the Truman Doctrine (a U.S. foreign policy pledging to aid nations threatened by Soviet expansionism) was announced, and 1991, the year the Soviet Union collapsed.
Relevant evidence: No