Year per person 1800 1.102 1820 1.125 1913 2.509 1950 4.916 1973 6.248 1990 6.16 1991 5.343 1992 3.164 1993 3.017 1994 3.287 1995 3.58 1996 3.797 1997 3.928 1998 4.229 1999 4.371 2000 4.636 2001 5.106 2002 5.904 2003 6.752 2004 7.487 2005 8.559 2006 9.678 2007 10.99 2008 11.71 2009 9.92