Year Percent 1960-01-01 89.4408 1961-01-01 89.2578 1962-01-01 89.9215 1963-01-01 90.8638 1964-01-01 91.2362 1965-01-01 92.3361 1966-01-01 92.5553 1967-01-01 92.4738 1968-01-01 93.6055 1969-01-01 94.1902 1970-01-01 95.1743 1971-01-01 96.2829 1972-01-01 96.7336 1973-01-01 97.3389 1974-01-01 97.8268 1975-01-01 97.3692 1976-01-01 97.0804 1977-01-01 97.7004 1978-01-01 98.4666 1979-01-01 98.7770 1980-01-01 98.9012 1981-01-01 99.2496 1982-01-01 99.3533 1983-01-01 99.0252 1984-01-01 98.6082 1985-01-01 98.4881 1986-01-01 98.6643 1987-01-01 98.7305 1988-01-01 98.8196 1989-01-01 98.9762 1990-01-01 98.9398 1991-01-01 98.8833 1992-01-01 98.8299 1993-01-01 98.8328 1994-01-01 98.9879 1995-01-01 99.1118 1996-01-01 99.1421 1997-01-01 99.1254 1998-01-01 99.1254 1999-01-01 99.6907 2000-01-01 99.7059 2001-01-01 99.7233 2002-01-01 99.7396 2003-01-01 99.7046 2004-01-01 99.6419 2005-01-01 99.6100 2006-01-01 99.5868 2007-01-01 99.5565 2008-01-01 99.4212 2009-01-01 99.2687 2010-01-01 99.1102 2011-01-01 98.5852 2012-01-01 97.8626 2013-01-01 97.8151 2014-01-01 98.1774 2015-01-01 96.6007 2016-01-01 92.4909