Year Percent 1991-01-01 38.3036 1992-01-01 21.6102 1993-01-01 27.0244 1994-01-01 32.9707 1995-01-01 32.3229 1996-01-01 34.8903 1997-01-01 34.6682 1998-01-01 37.2004 1999-01-01 39.6557 2000-01-01 42.6475 2001-01-01 44.8015 2002-01-01 46.3710 2003-01-01 48.2298 2004-01-01 53.1313 2005-01-01 58.4778 2006-01-01 64.7754 2007-01-01 70.2525 2008-01-01 78.4993 2009-01-01 90.6578 2010-01-01 95.3324 2011-01-01 95.2196 2012-01-01 97.0001 2013-01-01 90.7531 2014-01-01 79.2727 2015-01-01 71.5291 2016-01-01 65.3163