Year Percent 1980-01-01 0.385276000000000000 1981-01-01 0.411699000000000000 1982-01-01 0.411699000000000000 1983-01-01 0.411699000000000000 1984-01-01 0.411699000000000000 1985-01-01 0.411699000000000000 1986-01-01 0.411699000000000000 1987-01-01 0.411699000000000000 1988-01-01 0.411699000000000000 1989-01-01 0.411699000000000000 1990-01-01 0.411699000000000000 1991-01-01 0.411699000000000000 1992-01-01 0.411699000000000000 1993-01-01 0.411699000000000000 1994-01-01 0.411699000000000000 1995-01-01 0.411699000000000000 1996-01-01 0.411699000000000000 1997-01-01 0.411699000000000000 1998-01-01 0.411699000000000000 1999-01-01 0.411699000000000000 2000-01-01 0.411699000000000000 2001-01-01 0.036157999999999996 2002-01-01 0.075728000000000000 2003-01-01 0.187098000000000010 2004-01-01 0.309168000000000000 2005-01-01 0.277393000000000000 2006-01-01 0.239344999999999970 2007-01-01 0.222136000000000000 2008-01-01 0.183786999999999980 2009-01-01 0.163640000000000000 2010-01-01 0.144170000000000000 2011-01-01 0.103830999999999990 2012-01-01 0.081646000000000010 2013-01-01 0.066190000000000000 2014-01-01 0.052383000000000006 2015-01-01 0.051717999999999990 2016-01-01 0.046851000000000000