Year	Ratio
1970-01-01	0.750729978084564
1971-01-01	0.764890015125275
1972-01-01	0.739700019359589
1973-01-01	0.746940016746521
1974-01-01	0.779640018939972
1975-01-01	0.815639972686768
1976-01-01	0.848129987716675
1977-01-01	0.888119995594025
1998-01-01	1.003110051155090
1999-01-01	0.995760023593903
2000-01-01	1.003579974174500
2001-01-01	1.006309986114500
2002-01-01	1.020359992980960
2003-01-01	1.014009952545170
2004-01-01	0.973699986934662
2005-01-01	1.011450052261350
2006-01-01	1.015910029411320
2007-01-01	0.900009989738464
2009-01-01	1.003340005874630
2010-01-01	0.991840004920959
2011-01-01	0.965229988098145
2012-01-01	0.958660006523132
2013-01-01	0.975220024585724
2014-01-01	0.986450016498566
2015-01-01	0.993690013885498