Year Percent 1960-01-01 10.9600000000000000 1961-01-01 10.1087000000000000 1962-01-01 7.9166700000000000 1963-01-01 5.2924200000000000 1964-01-01 3.8192000000000000 1965-01-01 3.2381000000000000 1966-01-01 3.2436500000000000 1967-01-01 3.5025100000000000 1968-01-01 3.0104300000000000 1969-01-01 3.4855000000000000 1970-01-01 4.7608900000000000 1971-01-01 5.6200800000000010 1972-01-01 6.4108900000000000 1973-01-01 7.8661000000000000 1974-01-01 8.1549199999999990 1975-01-01 13.6454000000000000 1976-01-01 13.1807000000000000 1977-01-01 13.0685000000000000 1978-01-01 16.2561000000000000 1979-01-01 11.9512000000000000 1980-01-01 11.9512000000000000 1981-01-01 11.9512000000000000 1982-01-01 11.9512000000000000 1983-01-01 11.9512000000000000 1984-01-01 11.9512000000000000 1985-01-01 11.9512000000000000 1986-01-01 11.9512000000000000 1987-01-01 11.9512000000000000 1988-01-01 11.9512000000000000 1989-01-01 11.9512000000000000 1990-01-01 11.9512000000000000 1991-01-01 11.9512000000000000 1992-01-01 11.9512000000000000 1993-01-01 11.9512000000000000 1994-01-01 11.9512000000000000 1995-01-01 11.9512000000000000 1996-01-01 11.9512000000000000 1997-01-01 11.9512000000000000 1998-01-01 11.9512000000000000 1999-01-01 11.9512000000000000 2000-01-01 22.6619000000000000 2001-01-01 19.5999000000000000 2002-01-01 14.8638000000000000 2003-01-01 12.8367000000000000 2004-01-01 10.2758000000000000 2005-01-01 7.8741500000000000 2006-01-01 6.3695400000000000 2007-01-01 5.8529800000000005 2008-01-01 7.2478800000000000 2009-01-01 12.6250000000000000 2010-01-01 9.8999000000000000 2011-01-01 22.3241000000000000 2012-01-01 9.2954400000000000 2013-01-01 18.3059999999999970 2014-01-01 18.3059999999999970 2015-01-01 58.8318000000000000 2016-01-01 48.4030000000000000