Year	Percent
1991-01-01	61.9860000610352
1992-01-01	62.0839996337891
1993-01-01	63.3590011596680
1994-01-01	62.2410011291504
1995-01-01	59.7210006713867
1996-01-01	60.2970008850098
1997-01-01	59.6269989013672
1998-01-01	58.0900001525879
1999-01-01	54.7340011596680
2000-01-01	54.6529998779297
2001-01-01	52.0649986267090
2002-01-01	58.3530006408691
2003-01-01	65.6869964599609
2004-01-01	65.5189971923828
2005-01-01	64.6709976196289
2006-01-01	59.6209983825684
2007-01-01	57.6259994506836
2008-01-01	56.3390007019043
2009-01-01	55.1100006103516
2010-01-01	53.6850013732910
2011-01-01	55.2970008850098
2012-01-01	53.8689994812012
2013-01-01	51.8450012207031
2014-01-01	53.0890007019043
2015-01-01	47.3089981079102
2016-01-01	48.1940002441406
2017-01-01	46.9500007629395