Year	Ratio
1971-01-01	0.549639999866486
1972-01-01	0.551569998264313
1973-01-01	0.559409976005554
1974-01-01	0.575919985771179
1975-01-01	0.577690005302429
1976-01-01	0.569190025329590
1977-01-01	0.566299974918365
1978-01-01	0.565789997577667
1979-01-01	0.610210001468658
1980-01-01	0.580479979515076
1981-01-01	0.576189994812012
1982-01-01	0.585039973258972
1983-01-01	0.596830010414124
1984-01-01	0.575349986553192
1985-01-01	0.581390023231506
1986-01-01	0.585259974002838
1987-01-01	0.575410008430481
1988-01-01	0.566569983959198
1989-01-01	0.584159970283508
1990-01-01	0.594009995460510
1991-01-01	0.596729993820190
1992-01-01	0.603190004825592
1993-01-01	0.605459988117218
1994-01-01	0.574140012264252
1995-01-01	0.621739983558655
1996-01-01	0.624539971351624
1997-01-01	0.636969983577728
1998-01-01	0.651780009269714
1999-01-01	0.668449997901917
2000-01-01	0.676769971847534
2001-01-01	0.684249997138977
2002-01-01	0.685299992561340
2003-01-01	0.694589972496033
2004-01-01	0.700739979743958
2005-01-01	0.715489983558655
2006-01-01	0.725000023841858
2007-01-01	0.735360026359558
2008-01-01	0.771589994430542
2009-01-01	0.787980020046234
2010-01-01	0.811249971389771
2011-01-01	0.824519991874695
2012-01-01	0.835959970951080
2013-01-01	0.839739978313446
2014-01-01	0.851939976215363
2015-01-01	0.852989971637726
2016-01-01	0.860909998416901