Year Percent 1980-01-01 64.4328 1981-01-01 67.1928 1982-01-01 71.5341 1983-01-01 77.1197 1984-01-01 86.0739 1985-01-01 91.4668 1986-01-01 89.6562 1987-01-01 87.3134 1988-01-01 87.9516 1989-01-01 90.0590 1990-01-01 92.4134 1991-01-01 94.2741 1992-01-01 94.8512 1993-01-01 94.7159 1994-01-01 95.6850 1995-01-01 97.3188 1996-01-01 98.3676 1997-01-01 98.5953 1998-01-01 96.4407 1999-01-01 78.6957 2000-01-01 71.3999 2001-01-01 72.8508 2002-01-01 69.8292 2003-01-01 70.8827 2004-01-01 73.6413 2005-01-01 75.4228 2006-01-01 77.4237 2007-01-01 80.3744 2008-01-01 83.6017 2009-01-01 85.3238 2010-01-01 86.5862 2011-01-01 87.6629 2012-01-01 88.6903 2013-01-01 90.1386 2014-01-01 91.1986 2015-01-01 91.9994 2016-01-01 92.7693