Year Percent 1983-01-01 32.8834000000000000 1984-01-01 30.5075000000000000 1985-01-01 28.1207000000000000 1986-01-01 39.6924000000000000 1987-01-01 41.7895000000000000 1988-01-01 37.4761000000000000 1989-01-01 34.2185000000000000 1990-01-01 29.9692000000000000 1991-01-01 25.3898000000000000 1992-01-01 20.4564000000000000 1993-01-01 16.3367000000000000 1994-01-01 14.7394000000000000 1995-01-01 12.4564000000000000 1996-01-01 13.6426000000000000 1997-01-01 13.1106000000000000 1998-01-01 13.5512000000000000 1999-01-01 11.9706000000000000 2000-01-01 9.0290800000000000 2001-01-01 5.7789000000000000 2002-01-01 5.3382000000000000 2003-01-01 4.9086000000000000 2004-01-01 5.4793900000000000 2005-01-01 5.8712900000000000 2006-01-01 6.2710900000000000 2007-01-01 6.6813300000000000 2008-01-01 4.6484400000000000 2009-01-01 4.7681000000000000 2010-01-01 4.2742900000000010 2011-01-01 3.8182699999999996 2012-01-01 4.3693599999999995 2013-01-01 4.5587400000000000 2014-01-01 5.6433599999999995 2015-01-01 6.1241300000000000 2016-01-01 6.9182200000000000