Year	Ratio
1971-01-01	0.289469987154007
1973-01-01	0.293999999761581
1976-01-01	0.332679986953735
1977-01-01	0.358630001544952
1978-01-01	0.360159993171692
1979-01-01	0.380160003900528
1980-01-01	0.377330005168915
1981-01-01	0.389180004596710
1982-01-01	0.419120013713837
1983-01-01	0.418199986219406
1984-01-01	0.418810009956360
1985-01-01	0.449600011110306
1986-01-01	0.462660014629364
1987-01-01	0.459789991378784
1988-01-01	0.497810006141663
1989-01-01	0.504339993000031
1990-01-01	0.520860016345978
1991-01-01	0.535579979419708
1995-01-01	0.568650007247925
1996-01-01	0.609690010547638
1997-01-01	0.615279972553253
2000-01-01	0.655560016632080
2001-01-01	0.680750012397766
2002-01-01	0.693910002708435
2003-01-01	0.675390005111694
2004-01-01	0.668619990348816
2005-01-01	0.703880012035370
2006-01-01	0.718760013580322
2007-01-01	0.695789992809296
2009-01-01	0.703490018844604
2010-01-01	0.726189970970154
2011-01-01	0.783959984779358
2013-01-01	0.936129987239838
2014-01-01	0.983099997043610
2015-01-01	0.989979982376099
2016-01-01	1.002159953117370