Year US Dollars 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 0 1988 0 1989 0 1990 0 1991 0 1992 9731000 1993 385190000 1994 580286000 1995 633564000 1996 699361000 1997 1065027000 1998 1242772000 1999 1381613000 2000 1141071000 2001 1162076000 2002 1252992000 2003 1269664000 2004 1163509000 2005 1121433000 2006 1068155000 2007 1344269000 2008 2492573000 2009 2666449000 2010 3561643000 2011 3923584000 2012 4620535000 2013 4868394000 2014 5177945000 2015 5001714000 2016 4876658000