Year	Ratio
1971-01-01	0.979889988899231
1972-01-01	1.041139960289000
1973-01-01	0.950540006160736
1974-01-01	0.927839994430542
1990-01-01	0.964039981365204
1991-01-01	0.969039976596832
1992-01-01	0.971459984779358
1993-01-01	0.969099998474121
1999-01-01	0.953400015830994
2000-01-01	0.958410024642944
2001-01-01	0.964479982852936
2002-01-01	0.946839988231659
2003-01-01	0.935699999332428
2004-01-01	0.933089971542358
2005-01-01	0.939790010452271
2006-01-01	0.962440013885498
2007-01-01	0.949880003929138
2008-01-01	0.957849979400635
2009-01-01	0.966419994831085
2010-01-01	0.981660008430481
2011-01-01	0.986980020999908
2012-01-01	0.982879996299744
2013-01-01	0.987060010433197
2014-01-01	0.992250025272369
2015-01-01	0.984910011291504
2016-01-01	0.987249970436096