Year Percent 1988-01-01 3.4625800000000004 1989-01-01 3.1475200000000000 1990-01-01 1.6365299999999998 1991-01-01 0.5274060000000000 1992-01-01 0.3698610000000000 1993-01-01 0.3258430000000000 1994-01-01 1.2609500000000000 1995-01-01 1.9238900000000000 1996-01-01 1.6191700000000000 1997-01-01 1.2509000000000000 1998-01-01 1.3108600000000001 1999-01-01 1.3902100000000000 2000-01-01 1.4966600000000000 2001-01-01 1.4459400000000000 2002-01-01 1.1295600000000001 2003-01-01 0.9291080000000000 2004-01-01 0.8881899999999999 2005-01-01 1.0383700000000000 2006-01-01 4.3882000000000000 2007-01-01 7.6171899999999990 2008-01-01 7.6083600000000000 2009-01-01 10.2079000000000000 2010-01-01 11.3717000000000000 2011-01-01 9.8708600000000000 2012-01-01 8.7875100000000010 2013-01-01 7.8634900000000000 2014-01-01 6.8176900000000000 2015-01-01 6.2129900000000005 2016-01-01 6.1075000000000000