Year Percent 1960-01-01 9.24949000000000000 1961-01-01 8.95844000000000000 1962-01-01 8.38230000000000000 1963-01-01 8.32545000000000000 1964-01-01 7.61477000000000000 1965-01-01 7.13863000000000000 1966-01-01 7.44493000000000000 1967-01-01 6.87430000000000000 1968-01-01 7.10441000000000100 1969-01-01 9.72663000000000000 1970-01-01 10.40420000000000000 1971-01-01 9.66053000000000000 1972-01-01 9.41151000000000000 1973-01-01 8.04700000000000000 1974-01-01 7.12303000000000000 1975-01-01 7.78557000000000000 1976-01-01 6.09153000000000060 1977-01-01 4.54935000000000000 1978-01-01 4.13922000000000000 1979-01-01 3.96585000000000000 1980-01-01 3.35691000000000000 1981-01-01 4.26802000000000000 1982-01-01 4.26012000000000000 1983-01-01 7.43846000000000100 1984-01-01 10.45820000000000000 1985-01-01 9.24218999999999900 1986-01-01 10.74520000000000000 1987-01-01 8.06185000000000000 1988-01-01 9.84603999999999900 1989-01-01 12.15599999999999900 1990-01-01 8.07001000000000000 1991-01-01 5.86039000000000000 1992-01-01 5.19323000000000100 1993-01-01 12.46000000000000000 1994-01-01 19.48170000000000000 1995-01-01 10.32570000000000000 1996-01-01 0.80710400000000000 1997-01-01 0.61293000000000000 1998-01-01 0.81166100000000000 1999-01-01 4.13800000000000000 2000-01-01 9.75711000000000000 2001-01-01 5.84753000000000000 2002-01-01 4.36008000000000000 2003-01-01 3.79849000000000000 2004-01-01 3.54580000000000000 2005-01-01 3.15983000000000000 2006-01-01 2.66530000000000000 2007-01-01 2.34737000000000000 2008-01-01 1.08722000000000000 2009-01-01 0.19350000000000000 2010-01-01 0.27186900000000000 2011-01-01 0.23813900000000000 2012-01-01 0.21841100000000002 2013-01-01 0.19890000000000000 2014-01-01 0.57918200000000000 2015-01-01 1.22143000000000000 2016-01-01 2.98482000000000000