Year	Ratio
1971-01-01	0.287809997797012
1972-01-01	0.330320000648499
1973-01-01	0.319609999656677
1974-01-01	0.340440005064011
1976-01-01	0.357540011405945
1978-01-01	0.382869988679886
1979-01-01	0.392419993877411
1980-01-01	0.396239995956421
1981-01-01	0.414920002222061
1982-01-01	0.398099988698959
1983-01-01	0.391589999198914
1984-01-01	0.407770007848740
1987-01-01	0.436710000038147
1988-01-01	0.417400002479553
1989-01-01	0.495130002498627
1990-01-01	0.500810027122498
1991-01-01	0.515739977359772
1992-01-01	0.457980006933212
1993-01-01	0.505420029163361
1994-01-01	0.494819998741150
1995-01-01	0.494019985198975
1996-01-01	0.518450021743774
1997-01-01	0.496710002422333
1998-01-01	0.510299980640411
1999-01-01	0.533270001411438
2000-01-01	0.557889997959137
2003-01-01	0.545149981975555
2004-01-01	0.595229983329773
2005-01-01	0.616400003433228
2006-01-01	0.615409970283508
2007-01-01	0.657989978790283
2008-01-01	0.645439982414246
2009-01-01	0.655659973621368
2010-01-01	0.687390029430389
2011-01-01	0.698740005493164
2013-01-01	0.782620012760162
2014-01-01	0.741150021553040
2015-01-01	0.792569994926453
2016-01-01	0.743889987468719