Year	Percent
1991-01-01	54.2490005493164
1992-01-01	54.8440017700195
1993-01-01	54.7080001831055
1994-01-01	56.4700012207031
1995-01-01	56.4840011596680
1996-01-01	55.4410018920898
1997-01-01	55.1980018615723
1998-01-01	55.2540016174316
1999-01-01	55.8720016479492
2000-01-01	55.7709999084473
2001-01-01	55.6290016174316
2002-01-01	55.9819984436035
2003-01-01	55.9440002441406
2004-01-01	53.4990005493164
2005-01-01	54.8330001831055
2006-01-01	55.4309997558594
2007-01-01	56.4949989318848
2008-01-01	57.1899986267090
2009-01-01	56.7980003356934
2010-01-01	57.0680007934570
2011-01-01	57.2849998474121
2012-01-01	57.3590011596680
2013-01-01	57.2130012512207
2014-01-01	56.7789993286133
2015-01-01	56.6629981994629
2016-01-01	56.7960014343262
2017-01-01	57.0149993896484