上游充通大 ANGHAI JLAO TONG UNIVET War,Nation and Nation-Stat Annual Amounts of International War from 1816 to 2001, weighted by number of countries 4 3.5 2 1.5 1 0.5 uoneN 1816 Year1, War, Nation and Nation-State 0 0.5 1 1.5 2 2.5 3 3.5 4 Nation months of war involvement Year Annual Amounts of International War from 1816 to 2001, weighted by number of countries