Year Percent 1995-01-01 15.5968 1996-01-01 13.1456 1997-01-01 12.3484 1998-01-01 13.2425 1999-01-01 12.3780 2000-01-01 10.8609 2001-01-01 10.7098 2002-01-01 12.8184 2003-01-01 15.2187 2004-01-01 17.9652 2005-01-01 20.1891 2006-01-01 23.6069 2007-01-01 25.9861 2008-01-01 24.8070 2009-01-01 26.4119 2010-01-01 28.4587 2011-01-01 26.6219 2012-01-01 28.2481 2013-01-01 30.7225 2014-01-01 31.2649 2015-01-01 31.5741 2016-01-01 33.0994