Year	Percent
1991-01-01	62.5320014953613
1992-01-01	63.3100013732910
1993-01-01	63.2589988708496
1994-01-01	63.2150001525879
1995-01-01	63.1689987182617
1996-01-01	63.1209983825684
1997-01-01	62.8149986267090
1998-01-01	63.1180000305176
1999-01-01	63.2709999084473
2000-01-01	63.4259986877441
2001-01-01	63.6100006103516
2002-01-01	63.3320007324219
2003-01-01	63.4430007934570
2004-01-01	63.0559997558594
2005-01-01	62.3269996643066
2006-01-01	62.4370002746582
2007-01-01	62.0890007019043
2008-01-01	62.6329994201660
2009-01-01	63.5719985961914
2010-01-01	64.0999984741211
2011-01-01	64.2480010986328
2012-01-01	64.5319976806641
2013-01-01	64.4270019531250
2014-01-01	64.3919982910156
2015-01-01	62.8499984741211
2016-01-01	63.6380004882813
2017-01-01	63.5120010375977