Year	Percent
1991-01-01	75.9240036010742
1992-01-01	75.8659973144531
1993-01-01	76.5199966430664
1994-01-01	77.1829986572266
1995-01-01	76.7979965209961
1996-01-01	78.8249969482422
1997-01-01	78.7440032958984
1998-01-01	78.6910018920898
1999-01-01	78.7360000610352
2000-01-01	78.4769973754883
2001-01-01	78.3990020751953
2002-01-01	78.1630020141602
2003-01-01	78.0360031127930
2004-01-01	77.8909988403320
2005-01-01	77.7819976806641
2006-01-01	77.5220031738281
2007-01-01	77.3629989624023
2008-01-01	77.3519973754883
2009-01-01	77.2190017700195
2010-01-01	77.1600036621094
2011-01-01	77.0940017700195
2012-01-01	77.0350036621094
2013-01-01	76.9820022583008
2014-01-01	76.9449996948242
2015-01-01	76.8679962158203
2016-01-01	76.6809997558594
2017-01-01	76.6240005493164