Year Percent 1991 4.47789 1992 4.47789 1993 4.47788 1994 4.47785 1995 4.47787 1996 4.47788 1997 4.47787 1998 2.55527 1999 2.55527 2000 2.55524 2001 2.55527 2002 2.55528 2003 2.55525 2004 2.55528 2005 2.55526 2006 2.55526 2007 2.55525 2008 2.88243 2009 2.89187 2010 2.89863 2011 2.99704 2012 3.00626 2013 2.98462 2014 2.95799 2015 2.92469 2016 2.88469 2017 2.8847