Year per Person 1980 21.688 1981 21.4616 1982 20.43618 1983 20.56642 1984 20.63319 1985 20.59388 1986 19.66839 1987 19.67772 1988 19.30492 1989 18.68925 1990 18.27813 1991 17.19666 1992 16.52773 1993 15.83114 1994 15.3806 1995 15.27485 1996 15.14183 1997 15.2967 1998 14.13687 1999 14.51299 2000 14.70017 2001 14.57555 2002 14.55104 2003 13.80331 2004 13.66101 2005 13.82905 2006 13.48486 2007 13.82173 2008 12.76712 2009 13.75781 2010 15.46337 2011 17.44185 2012 19.23227 2013 20.94956 2014 23.59576 2015 20.45899 2016 20.31608