Year Percent 1960-01-01 19.074700000000000 1961-01-01 18.671600000000000 1962-01-01 20.852200000000000 1963-01-01 23.080800000000000 1964-01-01 23.828700000000000 1965-01-01 23.323500000000000 1966-01-01 23.913100000000000 1967-01-01 26.156900000000000 1968-01-01 27.770400000000000 1969-01-01 28.146400000000000 1970-01-01 27.896700000000000 1971-01-01 30.199700000000000 1972-01-01 32.015300000000000 1973-01-01 28.645100000000000 1974-01-01 30.723500000000000 1975-01-01 31.151300000000000 1976-01-01 31.052700000000000 1977-01-01 32.517500000000000 1978-01-01 37.521700000000000 1979-01-01 41.286400000000000 1980-01-01 41.422200000000000 1981-01-01 44.641000000000005 1982-01-01 46.787600000000000 1983-01-01 49.119100000000000 1984-01-01 49.118500000000000 1985-01-01 50.304500000000000 1986-01-01 52.720600000000000 1987-01-01 56.999800000000000 1988-01-01 56.839600000000000 1989-01-01 58.520300000000000 1990-01-01 58.424100000000000 1991-01-01 52.464500000000000 1992-01-01 49.491900000000000 1993-01-01 48.540400000000000 1994-01-01 49.284600000000000 1995-01-01 51.868400000000000 1996-01-01 53.598900000000000 1997-01-01 53.316700000000000 1998-01-01 51.708700000000000 1999-01-01 52.170500000000000 2000-01-01 53.931800000000000 2001-01-01 72.831800000000000 2002-01-01 86.841300000000000 2003-01-01 81.031500000000000 2004-01-01 80.252900000000000 2005-01-01 84.722000000000010 2006-01-01 84.410200000000000 2007-01-01 88.484000000000000 2008-01-01 97.821700000000000 2009-01-01 106.929000000000000 2010-01-01 109.827999999999990 2011-01-01 104.333000000000000 2012-01-01 101.111000000000000 2013-01-01 104.880000000000000 2014-01-01 108.185000000000000 2015-01-01 99.373500000000000 2016-01-01 89.820500000000000