Year per Person 1997 42.13196 1998 41.43841 1999 40.79989 2000 42.50648 2001 41.93338 2002 41.40189 2003 41.11393 2004 40.59582 2005 39.8398 2006 39.72479 2007 39.1395 2008 38.32071 2009 36.36082 2010 35.29992 2011 34.73896 2012 34.18321 2013 32.55558 2014 32.04335 2015 31.55053 2016 31.07821