Year	Percent
1991-01-01	52.2389984130859
1992-01-01	52.7820014953613
1993-01-01	53.1119995117188
1994-01-01	52.7869987487793
1995-01-01	51.8909988403320
1996-01-01	52.0040016174316
1997-01-01	51.5000000000000
1998-01-01	50.1119995117188
1999-01-01	50.6689987182617
2000-01-01	49.8479995727539
2001-01-01	50.0670013427734
2002-01-01	49.5200004577637
2003-01-01	49.2029991149902
2004-01-01	49.4980010986328
2005-01-01	48.8919982910156
2006-01-01	50.0270004272461
2007-01-01	50.4140014648438
2008-01-01	49.7879981994629
2009-01-01	49.9930000305176
2010-01-01	50.1380004882813
2011-01-01	50.3940010070801
2012-01-01	50.4389991760254
2013-01-01	50.6500015258789
2014-01-01	50.6160011291504
2015-01-01	50.6720008850098
2016-01-01	50.8419990539551
2017-01-01	50.7519989013672