Year	Percent
1991-01-01	51.4480018615723
1992-01-01	51.1889991760254
1993-01-01	50.5600013732910
1994-01-01	49.9690017700195
1995-01-01	49.0610008239746
1996-01-01	50.1170005798340
1997-01-01	52.0299987792969
1998-01-01	52.1319999694824
1999-01-01	54.3429985046387
2000-01-01	55.7130012512207
2001-01-01	57.9189987182617
2002-01-01	54.4840011596680
2003-01-01	57.4700012207031
2004-01-01	58.3440017700195
2005-01-01	59.1259994506836
2006-01-01	59.3250007629395
2007-01-01	60.0190010070801
2008-01-01	59.6090011596680
2009-01-01	58.7599983215332
2010-01-01	59.3540000915527
2011-01-01	60.5890007019043
2012-01-01	61.8250007629395
2013-01-01	62.1500015258789
2014-01-01	62.9990005493164
2015-01-01	63.2729988098145
2016-01-01	63.5340003967285
2017-01-01	63.6619987487793