Year Percent 1980-01-01 11.20640000000000000 1981-01-01 17.79600000000000000 1982-01-01 19.43480000000000000 1983-01-01 11.08120000000000000 1984-01-01 7.23483999999999900 1985-01-01 5.83287000000000000 1986-01-01 5.99318000000000100 1987-01-01 5.73739000000000000 1988-01-01 3.80635000000000000 1989-01-01 2.67437999999999980 1990-01-01 1.55223000000000000 1991-01-01 1.40783000000000000 1992-01-01 1.15654000000000000 1993-01-01 0.84276200000000010 1994-01-01 1.75246000000000000 1995-01-01 0.85840100000000000 1996-01-01 0.76614300000000000 1997-01-01 0.46397700000000003 1998-01-01 0.42454400000000000 1999-01-01 3.00372000000000000 2000-01-01 2.47893000000000000 2001-01-01 2.89829000000000030 2002-01-01 0.63772900000000000 2003-01-01 2.23264000000000000 2004-01-01 1.18943000000000000 2005-01-01 2.02665999999999970 2006-01-01 2.99042000000000000 2007-01-01 3.94130000000000000 2008-01-01 4.86323000000000100 2009-01-01 5.56977000000000000 2010-01-01 5.60870999999999900 2011-01-01 5.42636000000000000 2012-01-01 4.30260000000000000 2013-01-01 3.83141000000000000 2014-01-01 2.90717000000000030 2015-01-01 2.97516000000000000 2016-01-01 1.72714000000000010