Year Percent 1973-01-01 0.0780316 1974-01-01 0.0971145 1975-01-01 0.1277637 1976-01-01 0.1360277 1977-01-01 0.1266862 1978-01-01 0.1103990 1979-01-01 0.0749365 1980-01-01 0.0661281