Year Percent 1962-01-01 59.720100000000000 1963-01-01 52.211200000000000 1964-01-01 33.736400000000000 1965-01-01 23.545300000000000 1966-01-01 12.780800000000000 1967-01-01 6.783700000000000 1968-01-01 17.896800000000000 1969-01-01 33.872600000000000 1970-01-01 39.970100000000000 1971-01-01 42.018400000000000 1972-01-01 44.783800000000000 1973-01-01 47.881400000000000 1974-01-01 53.553999999999995 1975-01-01 60.037000000000000 1976-01-01 63.247100000000000 1977-01-01 58.783000000000000 1978-01-01 55.524800000000000 1979-01-01 58.009300000000000 1980-01-01 59.451900000000000 1981-01-01 59.612100000000000 1982-01-01 57.012200000000000 1983-01-01 53.723200000000000 1984-01-01 55.602700000000000 1985-01-01 61.713400000000000 1986-01-01 65.349300000000000 1987-01-01 67.701000000000010 1988-01-01 63.561100000000000 1989-01-01 63.024300000000000 1990-01-01 69.564800000000000 1991-01-01 72.050100000000000 1992-01-01 71.946900000000000 1993-01-01 71.104900000000000 1994-01-01 68.121200000000000 1995-01-01 67.857400000000000 1996-01-01 70.797600000000000 1997-01-01 69.989100000000000 1998-01-01 70.045500000000000 1999-01-01 72.093800000000000 2000-01-01 73.073300000000000 2001-01-01 74.298600000000000 2002-01-01 77.314900000000000 2003-01-01 81.344100000000000 2004-01-01 84.225000000000000 2005-01-01 86.599300000000000 2006-01-01 92.170700000000000 2007-01-01 96.913800000000000 2008-01-01 96.633000000000000 2009-01-01 93.733300000000000 2010-01-01 92.013700000000000 2011-01-01 92.182800000000000 2012-01-01 92.211900000000000 2013-01-01 92.562500000000000 2014-01-01 93.690600000000000 2015-01-01 95.003999999999990 2016-01-01 95.580900000000000