Year Percent 1998-01-01 61.291500000000000 1999-01-01 61.023300000000000 2000-01-01 57.900000000000000 2001-01-01 41.000000000000000 2002-01-01 24.848000000000003 2003-01-01 18.169600000000000 2004-01-01 34.902900000000000 2005-01-01 32.131900000000000 2006-01-01 44.272000000000000 2007-01-01 52.668300000000000 2008-01-01 31.180999999999997 2009-01-01 32.277900000000000 2010-01-01 31.134300000000000 2011-01-01 31.775500000000000 2012-01-01 29.230200000000000