Year	Percent
1991-01-01	59.8740005493164
1992-01-01	59.2750015258789
1993-01-01	58.7050018310547
1994-01-01	58.8979988098145
1995-01-01	58.9360008239746
1996-01-01	58.6800003051758
1997-01-01	57.9150009155273
1998-01-01	56.9199981689453
1999-01-01	55.4430007934570
2000-01-01	54.8580017089844
2001-01-01	54.9690017700195
2002-01-01	55.4319992065430
2003-01-01	54.8930015563965
2004-01-01	54.2750015258789
2005-01-01	54.7809982299805
2006-01-01	55.0769996643066
2007-01-01	55.7260017395020
2008-01-01	55.9179992675781
2009-01-01	54.6990013122559
2010-01-01	54.1020011901855
2011-01-01	54.3190002441406
2012-01-01	54.5660018920898
2013-01-01	55.2290000915527
2014-01-01	55.8079986572266
2015-01-01	56.6090011596680
2016-01-01	57.7669982910156
2017-01-01	58.1969985961914