Year	Percent
1991-01-01	53.7929992675781
1992-01-01	53.8619995117188
1993-01-01	53.9900016784668
1994-01-01	54.0970001220703
1995-01-01	54.1660003662109
1996-01-01	54.4379997253418
1997-01-01	54.7029991149902
1998-01-01	54.9710006713867
1999-01-01	55.3139991760254
2000-01-01	55.5660018920898
2001-01-01	56.0200004577637
2002-01-01	55.2799987792969
2003-01-01	54.4300003051758
2004-01-01	53.3409996032715
2005-01-01	53.0330009460449
2006-01-01	53.0929985046387
2007-01-01	52.8260002136230
2008-01-01	53.5169982910156
2009-01-01	53.3030014038086
2010-01-01	53.7280006408691
2011-01-01	53.1459999084473
2012-01-01	53.2770004272461
2013-01-01	53.8940010070801
2014-01-01	54.5779991149902
2015-01-01	54.9339981079102
2016-01-01	54.6609992980957
2017-01-01	54.5009994506836