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 15515000 1982 17123000 1983 18910000 1984 20295000 1985 23113000 1986 31803000 1987 46730000 1988 57461000 1989 65675000 1990 79177000 1991 82342000 1992 97983000 1993 100853000 1994 113598000 1995 128274000 1996 141574000 1997 152939000 1998 183325000 1999 185311000 2000 222227000 2001 252570000 2002 286807000 2003 331848000 2004 355539000 2005 415674000 2006 369061000 2007 474858000 2008 832194000 2009 433129000 2010 579623000 2011 451198000 2012 429781000 2013 474018000 2014 529296000 2015 533526000 2016 551039000