Year Percent 1980-01-01 11.73780000000000000 1981-01-01 11.87650000000000000 1982-01-01 14.80140000000000000 1983-01-01 14.75430000000000000 1984-01-01 16.08320000000000000 1985-01-01 22.56480000000000000 1986-01-01 29.63760000000000000 1987-01-01 26.43090000000000000 1988-01-01 21.96430000000000000 1989-01-01 20.74820000000000000 1990-01-01 21.32790000000000000 1991-01-01 20.47990000000000000 1992-01-01 17.11510000000000000 1993-01-01 17.52090000000000000 1994-01-01 14.54340000000000000 1995-01-01 9.77028000000000000 1996-01-01 6.90009000000000000 1997-01-01 5.63433000000000000 1998-01-01 6.43685000000000000 1999-01-01 5.31120000000000000 2000-01-01 5.31271000000000000 2001-01-01 4.45416000000000000 2002-01-01 3.79408000000000000 2003-01-01 3.44078000000000000 2004-01-01 2.48291000000000000 2005-01-01 1.44445000000000000 2006-01-01 1.13460000000000000 2007-01-01 0.94674900000000000 2008-01-01 0.58083900000000000 2009-01-01 0.64306500000000000 2010-01-01 0.54221200000000000 2011-01-01 0.48679799999999995 2012-01-01 0.75669900000000000 2013-01-01 0.47738600000000000 2014-01-01 0.61221600000000000 2015-01-01 0.71803400000000010 2016-01-01 0.65661800000000000