Year Percent 1960-01-01 17.855000000000000 1961-01-01 17.449100000000000 1962-01-01 17.295900000000000 1963-01-01 17.713700000000000 1964-01-01 18.123800000000000 1965-01-01 19.491800000000000 1966-01-01 23.488000000000003 1967-01-01 28.068400000000000 1968-01-01 29.681400000000000 1969-01-01 30.797100000000000 1970-01-01 31.940000000000000 1971-01-01 32.653100000000000 1972-01-01 34.907200000000000 1973-01-01 36.521000000000000 1974-01-01 40.123800000000000 1975-01-01 44.708600000000000 1976-01-01 45.583500000000000 1977-01-01 53.859600000000000 1978-01-01 62.417700000000000 1979-01-01 64.811500000000000 1980-01-01 66.511700000000000 1981-01-01 73.015600000000000 1982-01-01 81.284200000000000 1983-01-01 75.550700000000000 1984-01-01 72.481700000000000 1985-01-01 73.111000000000000 1986-01-01 75.027100000000000 1987-01-01 74.816900000000000 1988-01-01 76.345100000000000 1989-01-01 80.738800000000000 1990-01-01 86.100700000000000 1991-01-01 91.672500000000000 1992-01-01 91.988700000000000 1993-01-01 91.457700000000000 1994-01-01 88.569500000000000 1995-01-01 88.885000000000000 1996-01-01 91.214200000000000 1997-01-01 94.797800000000000 1998-01-01 96.977100000000000 1999-01-01 94.431800000000000 2000-01-01 91.077200000000000 2001-01-01 132.618000000000000 2002-01-01 168.270000000000000 2003-01-01 161.826000000000000 2004-01-01 159.043999999999980 2005-01-01 164.470999999999980 2006-01-01 177.310000000000000 2007-01-01 152.801000000000020 2008-01-01 122.694000000000000