Year Percent 1980-01-01 0.02984300000000000 1981-01-01 0.14912500000000000 1982-01-01 0.93614000000000000 1983-01-01 1.52215000000000000 1984-01-01 1.52720000000000000 1985-01-01 2.85947000000000000 1986-01-01 3.31264000000000000 1987-01-01 3.68085000000000000 1988-01-01 6.05210000000000000 1989-01-01 7.68561000000000050 1990-01-01 7.06527000000000000 1991-01-01 9.43728999999999900 1992-01-01 7.99255000000000000 1993-01-01 5.40451000000000000 1994-01-01 4.95544000000000000 1995-01-01 5.17330000000000000 1996-01-01 4.84296999999999900 1997-01-01 4.32548000000000100 1998-01-01 4.05978000000000000 1999-01-01 3.09905000000000000 2000-01-01 2.59854000000000030 2001-01-01 6.00111000000000000 2002-01-01 8.90892000000000000 2003-01-01 8.20457000000000000 2004-01-01 7.14235000000000000 2005-01-01 6.07872000000000000 2006-01-01 5.25406000000000000 2007-01-01 4.04558000000000000 2008-01-01 3.25258000000000000 2009-01-01 2.82783000000000000 2010-01-01 2.27827000000000000 2011-01-01 1.65773000000000000 2012-01-01 1.27369000000000000 2013-01-01 1.05667999999999980 2014-01-01 0.95173999999999990 2015-01-01 0.48555299999999996 2016-01-01 0.12628300000000000