Year Percent 1995-01-01 44.013999999999996 1996-01-01 41.448300000000000 1997-01-01 39.177000000000000 1998-01-01 27.671999999999997 1999-01-01 21.513800000000000 2000-01-01 20.615100000000000 2001-01-01 17.735900000000000 2002-01-01 14.940400000000000 2003-01-01 20.418600000000000 2004-01-01 21.260300000000000 2005-01-01 25.123100000000000 2006-01-01 20.591500000000000 2007-01-01 20.217900000000000 2008-01-01 19.799600000000000 2009-01-01 24.189200000000000 2010-01-01 11.860900000000000 2011-01-01 9.662289999999999 2012-01-01 19.052700000000000 2013-01-01 23.008000000000003 2014-01-01 19.164700000000000 2015-01-01 21.914400000000000 2016-01-01 21.196900000000000