Year	Percent
1991-01-01	54.0884198013095
1992-01-01	54.1808208497395
1993-01-01	53.6810991948140
1994-01-01	53.6494841024953
1995-01-01	53.3395843453184
1996-01-01	53.4180942560326
1997-01-01	53.1467638900022
1998-01-01	52.8971793553965
1999-01-01	53.6113282725980
2000-01-01	53.7470421831384
2001-01-01	53.6390906879634
2002-01-01	53.3313821305223
2003-01-01	53.7223446616278
2004-01-01	53.7921007330928
2005-01-01	54.2053620855872
2006-01-01	55.0980582864949
2007-01-01	55.4076351038446
2008-01-01	55.7224013428159
2009-01-01	55.5632053118056
2010-01-01	55.8363016790257
2011-01-01	56.1382168882979
2012-01-01	56.6306521735261
2013-01-01	56.7667130772127
2014-01-01	57.1358811144529
2015-01-01	57.3587310213102
2016-01-01	57.3154882067315
2017-01-01	57.4974650246010