Year Percent 1996-01-01 61.111100000000000 1997-01-01 74.444400000000000 1998-01-01 66.144200000000000 1999-01-01 59.090900000000000 2000-01-01 56.872000000000000 2001-01-01 56.291400000000000 2002-01-01 60.360400000000000 2003-01-01 59.971700000000000 2004-01-01 61.195900000000000 2005-01-01 52.204200000000000 2006-01-01 53.358900000000000 2007-01-01 49.730200000000000 2008-01-01 58.246700000000000 2009-01-01 42.915000000000000 2010-01-01 53.361999999999995 2011-01-01 38.350300000000000 2012-01-01 36.549800000000000 2013-01-01 38.751200000000000 2014-01-01 38.832900000000000