Year Percent 1960-01-01 0.6400000000000000 1961-01-01 0.6884060000000001 1962-01-01 0.6770830000000000 1963-01-01 1.6570400000000000 1964-01-01 1.5635000000000000 1965-01-01 2.1772000000000000 1966-01-01 3.0842900000000000 1967-01-01 3.7881000000000000 1968-01-01 3.6888199999999998 1969-01-01 4.6208100000000000 1970-01-01 2.8458500000000000 1971-01-01 1.1438100000000000 1972-01-01 2.0613400000000000 1973-01-01 8.1160600000000010 1974-01-01 12.1346000000000000 1975-01-01 21.8768000000000000 1976-01-01 20.1274000000000000 1977-01-01 15.9568000000000000 1978-01-01 25.3108000000000000 1979-01-01 26.6510000000000000 1980-01-01 26.6510000000000000 1981-01-01 26.6510000000000000 1982-01-01 26.6510000000000000 1983-01-01 26.6510000000000000 1984-01-01 26.6510000000000000 1985-01-01 26.6510000000000000 1986-01-01 26.6510000000000000 1987-01-01 26.6510000000000000 1988-01-01 26.6510000000000000 1989-01-01 26.6510000000000000 1990-01-01 26.6510000000000000 1991-01-01 26.6510000000000000 1992-01-01 26.6510000000000000 1993-01-01 26.6510000000000000 1994-01-01 26.6510000000000000 1995-01-01 26.6510000000000000 1996-01-01 26.6510000000000000 1997-01-01 26.6510000000000000 1998-01-01 26.6510000000000000 1999-01-01 26.6510000000000000 2000-01-01 53.2505000000000000 2001-01-01 46.0603000000000000 2002-01-01 30.8758000000000000 2003-01-01 24.8358000000000000 2004-01-01 13.0859999999999990 2005-01-01 5.7349500000000000 2006-01-01 5.8164200000000000 2007-01-01 6.9014899999999990 2008-01-01 6.4671699999999990 2009-01-01 8.9495800000000010 2010-01-01 9.6587600000000010 2011-01-01 26.8322000000000000 2012-01-01 9.9549399999999990 2013-01-01 14.3259000000000000 2014-01-01 14.3259000000000000 2015-01-01 14.3259000000000000 2016-01-01 188.5920000000000000