Year	Percent
1991-01-01	51.1829986572266
1992-01-01	49.2480010986328
1993-01-01	49.5859985351563
1994-01-01	50.1669998168945
1995-01-01	48.7980003356934
1996-01-01	49.4650001525879
1997-01-01	50.0320014953613
1998-01-01	54.0540008544922
1999-01-01	52.7500000000000
2000-01-01	52.5149993896484
2001-01-01	52.2970008850098
2002-01-01	51.7099990844727
2003-01-01	51.9269981384277
2004-01-01	51.7330017089844
2005-01-01	52.0050010681152
2006-01-01	52.5870018005371
2007-01-01	52.7700004577637
2008-01-01	53.0359992980957
2009-01-01	52.5019989013672
2010-01-01	52.0200004577637
2011-01-01	52.1370010375977
2012-01-01	51.3870010375977
2013-01-01	52.5970001220703
2014-01-01	51.7089996337891
2015-01-01	51.3590011596680
2016-01-01	51.4090003967285
2017-01-01	51.3580017089844