Year	Percent
1991-01-01	59.4160003662109
1992-01-01	58.0299987792969
1993-01-01	57.5940017700195
1994-01-01	58.0439987182617
1995-01-01	58.2960014343262
1996-01-01	58.0429992675781
1997-01-01	58.5559997558594
1998-01-01	59.3250007629395
1999-01-01	60.1430015563965
2000-01-01	60.8129997253418
2001-01-01	60.6520004272461
2002-01-01	61.2470016479492
2003-01-01	61.9830017089844
2004-01-01	62.1839981079102
2005-01-01	62.1590003967285
2006-01-01	62.3650016784668
2007-01-01	62.9970016479492
2008-01-01	63.0810012817383
2009-01-01	61.1839981079102
2010-01-01	61.2140007019043
2011-01-01	61.3870010375977
2012-01-01	61.3790016174316
2013-01-01	61.4900016784668
2014-01-01	61.1599998474121
2015-01-01	61.0149993896484
2016-01-01	60.8129997253418
2017-01-01	61.0639991760254