Year Percent 1990-01-01 19.3189 1991-01-01 19.7886 1992-01-01 29.2228 1993-01-01 39.8794 1994-01-01 41.0360 1995-01-01 46.8147 1996-01-01 47.7836 1997-01-01 49.7780 1998-01-01 52.6751 1999-01-01 49.3384 2000-01-01 42.1502 2001-01-01 45.4415 2002-01-01 42.6059 2003-01-01 47.2056 2004-01-01 48.7063 2005-01-01 53.2912 2006-01-01 53.0264 2007-01-01 53.0620 2008-01-01 51.4513 2009-01-01 51.4796 2010-01-01 50.6874 2011-01-01 52.7279 2012-01-01 52.2530 2013-01-01 51.9926 2014-01-01 52.9483 2015-01-01 57.7787 2016-01-01 60.4457