Year	Ratio
1973-01-01	0.812219977378845
1977-01-01	0.495550006628037
1982-01-01	0.246209993958473
1985-01-01	0.291269987821579
1987-01-01	0.270990014076233
1992-01-01	0.326240003108978
1993-01-01	0.313320010900497
1994-01-01	0.313190013170242
1995-01-01	0.296600013971329
1996-01-01	0.280140012502670
2004-01-01	0.446830004453659
2005-01-01	0.482749998569489
2006-01-01	0.872879981994629
2007-01-01	0.604049980640411
2008-01-01	0.616729974746704
2009-01-01	0.614880025386810
2010-01-01	0.650229990482330
2011-01-01	0.621770024299622
2012-01-01	0.645669996738434
2013-01-01	0.665669977664948
2014-01-01	0.711759984493256
2015-01-01	0.729420006275177
2016-01-01	0.786689996719360