Year Percent 1998-01-01 19.2883 1999-01-01 21.2421 2000-01-01 33.0000 2001-01-01 26.6000 2002-01-01 20.9313 2003-01-01 20.1761 2004-01-01 29.2284 2005-01-01 33.1680 2006-01-01 33.4013 2007-01-01 25.0321 2008-01-01 32.5090 2009-01-01 26.4058 2010-01-01 30.4223 2011-01-01 32.5062 2012-01-01 28.5613