Year Percent 1980-01-01 2.3285900000000000 1981-01-01 2.0056200000000000 1982-01-01 1.6416900000000000 1983-01-01 1.6635900000000001 1984-01-01 3.1217700000000000 1985-01-01 5.3059600000000000 1986-01-01 9.3034900000000000 1987-01-01 14.1448000000000000 1988-01-01 15.6600000000000000 1989-01-01 14.1263000000000000 1990-01-01 9.3239399999999990 1991-01-01 8.7744400000000000 1992-01-01 6.3238100000000000 1993-01-01 8.3049800000000000 1994-01-01 5.9583300000000000 1995-01-01 5.6062000000000000 1996-01-01 7.2270900000000000 1997-01-01 5.5420300000000005 1998-01-01 7.0440100000000010 1999-01-01 9.5451500000000000 2000-01-01 9.2365300000000000 2001-01-01 10.3841000000000000 2002-01-01 10.2145000000000000 2003-01-01 8.2507700000000000 2004-01-01 6.9255400000000000 2005-01-01 5.7034699999999990 2006-01-01 6.2714800000000000 2007-01-01 9.3501200000000000 2008-01-01 7.0510500000000000 2009-01-01 13.8063000000000000 2010-01-01 11.6477000000000000 2011-01-01 10.1313000000000000 2012-01-01 10.2257000000000000 2013-01-01 11.5380000000000000 2014-01-01 10.8033000000000000 2015-01-01 12.3733000000000000 2016-01-01 21.2640000000000000