Year US Dollars 1970 8425113000 1971 9328752000 1972 10029275000 1973 10965920000 1974 12696942000 1975 13865608000 1976 14586391000 1977 15414652000 1978 16520246000 1979 18190374000 1980 20723348000 1981 22480056000 1982 26942857000 1983 30649486000 1984 32763964000 1985 38934796000 1986 44909437000 1987 53424898000 1988 59288512000 1989 73721054000 1990 83471510000 1991 84852339000 1992 87775433000 1993 91330322000 1994 97898637000 1995 93808992000 1996 93966079000 1997 94059303000 1998 98333658000 1999 99779503000 2000 101131480000 2001 99500089000 2002 105741612000 2003 118884623000 2004 123644482000 2005 121195475000 2006 159525523000 2007 204057533000 2008 227111767000 2009 256312230000 2010 290427553000 2011 334399295000 2012 392625128000 2013 427296379000 2014 457552597000 2015 478874627000 2016 456139934000