Year	Percent
1991-01-01	62.7070007324219
1992-01-01	62.7639999389648
1993-01-01	62.7729988098145
1994-01-01	62.7389984130859
1995-01-01	62.6150016784668
1996-01-01	62.6329994201660
1997-01-01	62.6069984436035
1998-01-01	62.5509986877441
1999-01-01	62.4609985351563
2000-01-01	62.3639984130859
2001-01-01	62.3359985351563
2002-01-01	62.2729988098145
2003-01-01	62.2220001220703
2004-01-01	62.1629981994629
2005-01-01	62.0950012207031
2006-01-01	62.0470008850098
2007-01-01	62.0040016174316
2008-01-01	61.9039993286133
2009-01-01	61.8520011901855
2010-01-01	61.7949981689453
2011-01-01	61.7340011596680
2012-01-01	61.6570014953613
2013-01-01	61.5789985656738
2014-01-01	61.5180015563965
2015-01-01	61.4560012817383
2016-01-01	61.3440017700195
2017-01-01	61.3409996032715