Year Percent 1989-01-01 26.344300000000000 1990-01-01 24.677000000000000 1991-01-01 23.437300000000000 1992-01-01 21.110800000000000 1993-01-01 21.526100000000000 1994-01-01 22.013400000000000 1995-01-01 21.399300000000000 1996-01-01 19.213400000000000 1997-01-01 20.600900000000000 1998-01-01 21.108400000000000 1999-01-01 18.411800000000000 2000-01-01 19.171900000000000 2001-01-01 18.410999999999998 2002-01-01 20.682900000000000 2003-01-01 19.898400000000000 2004-01-01 19.518300000000000 2005-01-01 15.960100000000000 2006-01-01 16.434200000000000 2007-01-01 15.891200000000000 2008-01-01 14.645600000000000 2009-01-01 15.173100000000000 2010-01-01 15.236700000000000 2011-01-01 12.405600000000000 2012-01-01 13.871100000000000 2013-01-01 15.059700000000000 2014-01-01 14.530600000000000 2015-01-01 16.724400000000000 2016-01-01 17.396700000000000