How many civilians died in the war during which USS "Felicia" was acquired by the U.S. Navy?
USS Felicia (SP-642): USS "Felicia" (SP-642) was a yacht acquired by the U.S. Navy during World War I. World War I:  Over nine million combatants and seven million civilians died as a result of the war (including the victims of a number of genocides), a casualty rate exacerbated by the belligerents' technological and industrial sophistication, and the tactical stalemate caused by gruelling trench warfare.
seven million