Year	Percent
1991-01-01	89.2419967651367
1992-01-01	88.8619995117188
1993-01-01	88.2939987182617
1994-01-01	87.7470016479492
1995-01-01	87.0179977416992
1996-01-01	86.6699981689453
1997-01-01	86.5319976806641
1998-01-01	86.5940017700195
1999-01-01	86.6480026245117
2000-01-01	86.5360031127930
2001-01-01	86.3310012817383
2002-01-01	85.9889984130859
2003-01-01	85.4240036010742
2004-01-01	84.8939971923828
2005-01-01	84.5479965209961
2006-01-01	84.3410034179688
2007-01-01	84.3079986572266
2008-01-01	84.3379974365234
2009-01-01	84.3479995727539
2010-01-01	84.2320022583008
2011-01-01	84.0680007934570
2012-01-01	83.8580017089844
2013-01-01	84.7639999389648
2014-01-01	85.5680007934570
2015-01-01	85.4089965820313
2016-01-01	85.1520004272461
2017-01-01	85.0350036621094