Year Percent 1963-01-01 32.4022400000000000 1964-01-01 33.1690700000000000 1965-01-01 30.6894500000000000 1966-01-01 27.6569900000000040 1967-01-01 27.3180800000000000 1968-01-01 28.4424900000000030 1969-01-01 28.8222200000000000 1970-01-01 27.1152099999999980 1971-01-01 32.5072400000000000 1972-01-01 42.1408599999999960 1973-01-01 45.8727800000000000 1974-01-01 47.6916100000000000 1975-01-01 46.9655500000000000 1976-01-01 41.7802400000000000 1977-01-01 35.3371900000000000 1978-01-01 31.4776800000000000 1979-01-01 27.9405200000000030 1980-01-01 29.4317500000000000 1981-01-01 27.4696700000000000 1982-01-01 27.4696700000000000 1983-01-01 27.4696700000000000 1984-01-01 25.3887900000000000 1985-01-01 28.3043800000000000 1986-01-01 28.1975600000000000 1987-01-01 42.6689900000000000 1988-01-01 30.8592200000000000 1989-01-01 19.2000700000000000 1990-01-01 11.5051100000000000 1991-01-01 6.4230599999999995 1992-01-01 4.7203029999999995 1993-01-01 5.5359169999999995 1994-01-01 17.1702000000000000 1995-01-01 43.4014600000000000 1996-01-01 43.4014600000000000 1997-01-01 43.4014600000000000 1998-01-01 43.4014600000000000 1999-01-01 43.4014600000000000 2000-01-01 8.8767910000000000 2001-01-01 37.2336800000000000 2002-01-01 38.7610700000000040 2003-01-01 49.5526800000000000 2004-01-01 39.8844900000000000 2005-01-01 40.1899600000000000 2006-01-01 53.0541699999999900 2007-01-01 64.9973000000000000 2008-01-01 75.2612300000000000 2009-01-01 83.1853100000000000 2010-01-01 94.0363100000000000 2011-01-01 61.0634800000000060 2012-01-01 47.7374900000000000 2013-01-01 55.4423199999999950 2014-01-01 63.3331300000000040