Year per Person 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0.5908 1978 3.14866 1979 4.56754 1980 5.52584 1981 5.47845 1982 5.2446 1983 5.15228 1984 5.64632 1985 5.67455 1986 5.63185 1987 6.05116 1988 6.0621 1989 6.12003 1990 5.39921 1991 5.2756 1992 5.41619 1993 5.17121 1994 5.56406 1995 5.73209 1996 7.66137 1997 8.74383 1998 8.94325 1999 9.75055 2000 9.96051 2001 10.75203 2002 12.98609 2003 14.36816 2004 15.49754 2005 16.67788 2006 17.07678 2007 17.22141 2008 18.8831 2009 19.46167 2010 19.75592 2011 18.42107 2012 20.60053 2013 19.27695 2014 19.05293 2015 20.27756 2016 19.97833