Year Percent 1960-01-01 31.19650000000000 1961-01-01 32.38810000000000 1962-01-01 30.80200000000000 1963-01-01 30.62780000000000 1964-01-01 29.97440000000000 1965-01-01 29.80000000000000 1966-01-01 30.80740000000000 1967-01-01 30.23200000000000 1968-01-01 29.88060000000000 1969-01-01 28.93810000000000 1970-01-01 25.35630000000000 1971-01-01 25.54850000000000 1972-01-01 27.92560000000000 1973-01-01 29.60740000000000 1974-01-01 28.36710000000000 1975-01-01 30.81910000000000 1976-01-01 31.20020000000000 1977-01-01 31.99920000000000 1978-01-01 34.35250000000000 1979-01-01 35.00270000000000 1980-01-01 32.94170000000000 1981-01-01 35.41470000000000 1982-01-01 34.46070000000000 1983-01-01 35.78310000000000 1984-01-01 36.75540000000000 1985-01-01 35.26220000000000 1986-01-01 34.49020000000000 1987-01-01 38.31070000000000 1988-01-01 37.26850000000000 1989-01-01 39.37100000000000 1990-01-01 42.05840000000000 1991-01-01 44.79260000000000 1992-01-01 49.44630000000000 1993-01-01 52.62410000000000 1994-01-01 51.23480000000000 1995-01-01 55.31930000000000 1996-01-01 51.82640000000000 1997-01-01 57.36270000000000 1998-01-01 59.53110000000000 1999-01-01 62.80900000000000 2000-01-01 68.26460000000000 2001-01-01 69.62870000000000 2002-01-01 74.32790000000000 2003-01-01 74.34890000000000 2004-01-01 76.09300000000000 2005-01-01 80.51180000000000 2006-01-01 85.65740000000000 2007-01-01 92.56420000000000 2008-01-01 95.29690000000000 2009-01-01 97.88970000000000 2010-01-01 102.19200000000001 2011-01-01 106.80300000000000 2012-01-01 108.76200000000000 2013-01-01 107.34000000000000 2014-01-01 108.56000000000000 2015-01-01 108.00200000000001 2016-01-01 110.81100000000000