Year	Ratio
1971-01-01	0.223989993333817
1972-01-01	0.259810000658035
1973-01-01	0.316969990730286
1974-01-01	0.388799995183945
1975-01-01	0.450659990310669
1976-01-01	0.517880022525787
1977-01-01	0.580280005931854
1978-01-01	0.644339978694916
1979-01-01	0.685490012168884
1980-01-01	0.708639979362488
1981-01-01	0.694199979305267
1983-01-01	0.739170014858246
1986-01-01	0.863160014152527
2002-01-01	1.064929962158200
2003-01-01	1.065150022506710
2005-01-01	1.191869974136350
2006-01-01	1.175480008125310