Year	Percent
1991-01-01	75.1819992065430
1992-01-01	75.5159988403320
1993-01-01	75.5039978027344
1994-01-01	75.4100036621094
1995-01-01	75.1090011596680
1996-01-01	74.8949966430664
1997-01-01	74.6569976806641
1998-01-01	74.2760009765625
1999-01-01	73.9680023193359
2000-01-01	73.7190017700195
2001-01-01	73.0260009765625
2002-01-01	72.3489990234375
2003-01-01	71.6330032348633
2004-01-01	70.8809967041016
2005-01-01	70.3410034179688
2006-01-01	69.8750000000000
2007-01-01	69.5830001831055
2008-01-01	68.7460021972656
2009-01-01	68.3870010375977
2010-01-01	67.9919967651367
2011-01-01	67.6740036010742
2012-01-01	67.3750000000000
2013-01-01	67.1090011596680
2014-01-01	66.8219985961914
2015-01-01	66.5210037231445
2016-01-01	66.1409988403320
2017-01-01	65.7089996337891