Year Percent 1983-01-01 14.2479 1984-01-01 16.1150 1985-01-01 15.8736 1986-01-01 15.2516 1987-01-01 17.4235 1988-01-01 19.3212 1989-01-01 22.5204 1990-01-01 24.3913 1991-01-01 25.5641 1992-01-01 30.2844 1993-01-01 32.1784 1994-01-01 33.0868 1995-01-01 30.5355 1996-01-01 25.3172 1997-01-01 27.6032 1998-01-01 28.0319 1999-01-01 22.6165 2000-01-01 20.0474 2001-01-01 22.1642 2002-01-01 24.7099 2003-01-01 28.8733 2004-01-01 33.9719 2005-01-01 37.9753 2006-01-01 44.5942 2007-01-01 53.3274 2008-01-01 64.2786 2009-01-01 57.8276 2010-01-01 57.6966 2011-01-01 74.0463 2012-01-01 84.7143 2013-01-01 87.0866 2014-01-01 81.5872 2015-01-01 79.6173 2016-01-01 81.4131