Year Percent 1977-01-01 1.2012700000000000 1978-01-01 6.8559100000000010 1979-01-01 9.0778300000000000 1980-01-01 5.9215700000000000 1981-01-01 2.8096000000000000 1982-01-01 2.5198000000000000 1983-01-01 2.1973700000000003 1984-01-01 1.8362500000000000 1985-01-01 2.1312500000000000 1986-01-01 2.4298100000000000 1987-01-01 2.9411200000000000 1988-01-01 3.4036000000000000 1989-01-01 4.3639800000000010 1990-01-01 3.1278900000000003 1991-01-01 2.6960800000000000 1992-01-01 4.1498300000000010 1993-01-01 2.5701000000000000 1994-01-01 5.2855099999999995 1995-01-01 2.9745400000000000 1996-01-01 2.2698300000000000 1997-01-01 1.6407900000000002 1998-01-01 1.4472900000000000 1999-01-01 1.2473299999999998 2000-01-01 0.9313930000000000 2001-01-01 0.8056939999999999 2002-01-01 0.6255140000000000 2003-01-01 4.0727199999999995 2004-01-01 3.4081500000000000 2005-01-01 2.8518000000000000 2006-01-01 2.3850400000000000 2007-01-01 2.5502800000000000 2008-01-01 2.5199000000000000 2009-01-01 2.5028099999999998 2010-01-01 2.7432300000000000