Year	Percent
1991-01-01	64.8099975585938
1992-01-01	61.7200012207031
1993-01-01	57.8680000305176
1994-01-01	57.1430015563965
1995-01-01	58.0289993286133
1996-01-01	57.4900016784668
1997-01-01	56.5649986267090
1998-01-01	57.1819992065430
1999-01-01	58.1920013427734
2000-01-01	58.9500007629395
2001-01-01	60.0989990234375
2002-01-01	59.9980010986328
2003-01-01	59.4809989929199
2004-01-01	58.8979988098145
2005-01-01	58.8339996337891
2006-01-01	58.8260002136230
2007-01-01	59.7400016784668
2008-01-01	59.8499984741211
2009-01-01	58.0340003967285
2010-01-01	57.6910018920898
2011-01-01	58.4329986572266
2012-01-01	58.3769989013672
2013-01-01	58.7309989929199
2014-01-01	58.8689994812012
2015-01-01	59.2109985351563
2016-01-01	59.5209999084473
2017-01-01	59.7360000610352