Year Percent 1962-01-01 0.05785900000000000000 1963-01-01 0.21639000000000000000 1964-01-01 0.41669700000000004000 1965-01-01 0.36400000000000000000 1966-01-01 0.49916800000000006000 1967-01-01 0.23024699999999998000 1968-01-01 0.09546500000000000000 1969-01-01 0.00127300000000000000 1970-01-01 0.00022200000000000003 1971-01-01 0.00020200000000000000 1972-01-01 0.00054700000000000000 1973-01-01 0.00030600000000000000 1974-01-01 0.00030600000000000000 1975-01-01 0.00030600000000000000 1976-01-01 0.00021200000000000000 1977-01-01 0.33987900000000000000 1978-01-01 0.79265800000000000000 1979-01-01 1.01280000000000000000 1980-01-01 1.09715000000000000000 1981-01-01 1.10846000000000000000 1982-01-01 1.44006000000000010000 1983-01-01 1.90899000000000020000 1984-01-01 2.16410000000000000000 1985-01-01 1.92219000000000000000 1986-01-01 1.75717000000000010000 1987-01-01 2.02166000000000000000 1988-01-01 2.20931000000000000000 1989-01-01 2.11374000000000000000 1990-01-01 2.20168000000000000000 1991-01-01 2.36655000000000000000 1992-01-01 2.50483000000000000000 1993-01-01 2.70619000000000030000 1994-01-01 3.59325000000000000000 1995-01-01 4.26011000000000000000 1996-01-01 4.40701999999999900000 1997-01-01 4.84857000000000000000 1998-01-01 5.38915000000000000000 1999-01-01 5.36135000000000000000 2000-01-01 5.51609000000000000000 2001-01-01 5.31347000000000000000 2002-01-01 5.11173000000000060000 2003-01-01 4.45786000000000000000 2004-01-01 3.82340000000000000000 2005-01-01 3.28946000000000000000 2006-01-01 2.23336000000000000000 2007-01-01 1.26803000000000000000 2008-01-01 1.15764000000000000000 2009-01-01 1.81398000000000000000 2010-01-01 2.27867000000000000000 2011-01-01 2.14515000000000000000 2012-01-01 2.24240000000000000000 2013-01-01 2.38117000000000000000 2014-01-01 2.21331000000000000000 2015-01-01 2.03463000000000000000 2016-01-01 1.92009000000000000000