Year Total 1985 28465000000 1986 29345000000 1987 29753000000 1988 31086000000 1989 31358000000 1990 32264000000 1991 33297000000 1992 32898000000 1993 34275000000 1994 34852000000 1995 36061000000 1996 36473000000 1997 37109000000 1998 37611000000 1999 37818000000.00001 2000 39247000000 2001 39571000000 2002 40630000000 2003 40778000000 2004 42703000000 2005 42902000000 2006 43449000000 2007 43798000000 2008 43835000000 2009 43436000000.00001 2010 44858999999.99999 2011 44418000000 2012 44321000000.00001 2013 43305000000 2014 43599000000 2015 44321000000.00001 2016 43910000000