Year Percent 1989-01-01 5.876250000000000 1990-01-01 7.894070000000000 1991-01-01 15.315000000000000 1992-01-01 16.847800000000000 1993-01-01 17.911200000000000 1994-01-01 22.648400000000000 1995-01-01 18.462300000000000 1996-01-01 13.529100000000000 1997-01-01 12.331000000000000 1998-01-01 11.437500000000000 1999-01-01 9.925620000000000 2000-01-01 7.685930000000000 2001-01-01 7.220389999999999 2002-01-01 8.862210000000001 2003-01-01 11.435100000000000 2004-01-01 14.616700000000000 2005-01-01 19.053000000000000 2006-01-01 23.318800000000000 2007-01-01 22.963700000000000 2008-01-01 15.813900000000000 2009-01-01 15.892800000000000 2010-01-01 25.743500000000000 2011-01-01 30.656200000000000 2012-01-01 24.963700000000000 2013-01-01 24.151100000000000 2014-01-01 26.412600000000000 2015-01-01 26.705200000000000 2016-01-01 22.949900000000000 2017-01-01 21.153400000000000