Year Percent 1996-01-01 30.000000000000000 1997-01-01 23.529400000000000 1998-01-01 21.951200000000000 1999-01-01 20.454500000000000 2000-01-01 25.730999999999998 2001-01-01 29.787200000000000 2002-01-01 30.932200000000000 2003-01-01 35.789500000000000 2004-01-01 47.407400000000000 2005-01-01 49.350700000000000 2006-01-01 40.587400000000000 2007-01-01 36.842300000000000 2008-01-01 36.219100000000000 2009-01-01 39.261700000000000 2010-01-01 43.299000000000000 2011-01-01 45.645900000000000 2012-01-01 44.392100000000000 2013-01-01 44.089700000000000 2014-01-01 42.016100000000000