Year Percent 1962-01-01 99.0596 1963-01-01 99.1266 1964-01-01 98.8228 1965-01-01 99.1062 1966-01-01 99.1062 1967-01-01 97.9783 1968-01-01 99.8223 1969-01-01 99.8223 1970-01-01 99.8223 1971-01-01 99.8223 1972-01-01 99.9839 1973-01-01 99.9822 1974-01-01 99.9651 1975-01-01 94.6088 1976-01-01 91.9899 1977-01-01 89.8872 1978-01-01 85.0073 1979-01-01 82.5406 1980-01-01 83.1939 1981-01-01 79.7456 1982-01-01 75.6136 1983-01-01 72.3540 1984-01-01 68.5991 1985-01-01 65.9206 1986-01-01 65.7765 1987-01-01 68.6679 1988-01-01 69.9262 1989-01-01 70.6739 1990-01-01 70.7945 1991-01-01 72.4018 1992-01-01 73.9827 1993-01-01 72.9142 1994-01-01 71.0018 1995-01-01 68.0264 1996-01-01 67.9145 1997-01-01 70.6664 1998-01-01 71.0444 1999-01-01 70.1412 2000-01-01 70.3071 2001-01-01 71.1250 2002-01-01 73.4114 2003-01-01 78.3407 2004-01-01 83.9251 2005-01-01 88.5166 2006-01-01 91.1950 2007-01-01 93.2403 2008-01-01 93.5718 2009-01-01 88.6828 2010-01-01 84.5269 2011-01-01 84.3203 2012-01-01 86.2281 2013-01-01 88.4585 2014-01-01 90.5733 2015-01-01 92.6197 2016-01-01 94.5827