Year Percent 1987-01-01 0.037068000000000004 1988-01-01 0.030924000000000000 1989-01-01 0.032493000000000000 1990-01-01 0.029858999999999997 1991-01-01 0.028547000000000003 1992-01-01 0.024505000000000002 1993-01-01 0.023334000000000000 1994-01-01 0.024340999999999998 1995-01-01 0.025209000000000000 1996-01-01 0.022827000000000000 1997-01-01 0.007188000000000000 1998-01-01 0.007159000000000000 1999-01-01 0.009904999999999999 2000-01-01 0.009132000000000000 2001-01-01 0.007441000000000000 2002-01-01 0.008142000000000000 2003-01-01 0.047269000000000000 2004-01-01 0.055486000000000000 2005-01-01 0.049022000000000000 2006-01-01 0.931350000000000000 2007-01-01 0.898991000000000000 2008-01-01 3.004600000000000000 2009-01-01 2.695010000000000000 2010-01-01 2.703999999999999700 2011-01-01 2.833560000000000000 2012-01-01 3.766140000000000000 2013-01-01 2.048490000000000000 2014-01-01 1.616530000000000000 2015-01-01 1.790460000000000000 2016-01-01 1.063340000000000000