Year Percent 1982 0.01258 1990 0.4 1991 0.6 1992 1 1993 1.4 1994 1.7 1995 1.8 1996 1.9 1997 1.9 1998 1.8 1999 1.8 2000 1.7 2001 1.6 2002 1.5 2003 1.4 2004 1.3 2005 1.2 2006 1.1 2007 1.1 2008 1 2009 1.2 2010 1.1 2011 1.1