Year Percent 1992-01-01 14.6404 1993-01-01 22.9643 1994-01-01 11.7920 1995-01-01 13.2064 1996-01-01 10.4842 1997-01-01 11.8534 1998-01-01 12.5823 1999-01-01 10.6622 2000-01-01 12.8059 2001-01-01 13.6167 2002-01-01 12.0637 2003-01-01 12.2286 2004-01-01 14.0693 2005-01-01 13.0346 2006-01-01 13.6098 2007-01-01 16.0964 2008-01-01 19.3164 2009-01-01 23.2444 2010-01-01 22.1789 2011-01-01 23.9173 2012-01-01 28.1371 2013-01-01 30.0542 2014-01-01 31.6049 2015-01-01 36.8457 2016-01-01 34.3104