Year Percent 1980-01-01 0.30432800000000004 1981-01-01 0.41568000000000000 1982-01-01 0.55760500000000000 1983-01-01 1.37431000000000010 1984-01-01 2.93055000000000000 1985-01-01 4.93959000000000000 1986-01-01 6.18511000000000000 1987-01-01 5.54068000000000000 1988-01-01 5.29075000000000000 1989-01-01 5.47291000000000000 1990-01-01 5.45602000000000000 1991-01-01 6.13753000000000000 1992-01-01 5.24919000000000050 1993-01-01 7.13104000000000000 1994-01-01 7.92043999999999900 1995-01-01 7.17791000000000100 1996-01-01 5.55540000000000000 1997-01-01 5.76234000000000000 1998-01-01 4.79159000000000000 1999-01-01 3.36821000000000000 2000-01-01 3.12395000000000000 2001-01-01 6.02350000000000000 2002-01-01 7.52807000000000000 2003-01-01 6.68863999999999950 2004-01-01 6.13837000000000000 2005-01-01 5.01423000000000000 2006-01-01 3.68598000000000030 2007-01-01 5.07322000000000000 2008-01-01 6.01198000000000000 2009-01-01 8.87193999999999900 2010-01-01 10.01600000000000000 2011-01-01 8.06447000000000000 2012-01-01 6.22989000000000000 2013-01-01 6.04260000000000000 2014-01-01 4.18066000000000000 2015-01-01 4.51436000000000000 2016-01-01 4.27931999999999900