Year Ratio 1972-01-01 0.774879992008209 1973-01-01 0.838429987430573 1974-01-01 0.867479979991913 1976-01-01 0.944580018520355 1977-01-01 0.938459992408752 2004-01-01 1.062459945678710 2005-01-01 1.082620024681090