Year	Percent
1991-01-01	49.4020004272461
1992-01-01	51.1240005493164
1993-01-01	52.8199996948242
1994-01-01	52.6769981384277
1995-01-01	53.5929985046387
1996-01-01	53.4420013427734
1997-01-01	54.0690002441406
1998-01-01	53.7700004577637
1999-01-01	55.2700004577637
2000-01-01	54.4269981384277
2001-01-01	53.9430007934570
2002-01-01	54.5690002441406
2003-01-01	55.1230010986328
2004-01-01	56.2770004272461
2005-01-01	57.8769989013672
2006-01-01	57.8699989318848
2007-01-01	59.8549995422363
2008-01-01	61.9169998168945
2009-01-01	62.0699996948242
2010-01-01	61.5610008239746
2011-01-01	61.0589981079102
2012-01-01	62.4350013732910
2013-01-01	63.5810012817383
2014-01-01	62.8790016174316
2015-01-01	63.4830017089844
2016-01-01	63.9980010986328
2017-01-01	63.9220008850098