Year Percent 1990 1.1 1991 1.1 1992 1.1 1993 1.1 1994 1.1 1995 1.1 1996 1.1 1997 1.1 1998 1.1 1999 1.1 2000 1.1 2001 1.1 2002 1.1 2003 1.1 2004 1.1 2005 1.1 2006 1.1 2007 1.1 2008 1.1 2009 1.1 2010 1.1 2011 1.1 2012 1.1 2013 1.1 2014 1.1 2015 1.1