Year	current US$
1970	261262.380626018
1971	283777.735877571
1972	394293.350421532
1973	487165.228319941
1974	463430.612151645
1975	519028.335309137
1976	1676273.79758996
1977	1485082.87392967
1978	792204.149586753
1979	833549.71672236
1980	892926.713507608
1981	817647.414916533
1982	644494.346411917
1983	466020.018947925
1984	513009.097314158
1985	547232.522443737
1986	589735.285140033
1987	561146.660219256
1988	535301.066598804
1989	408936.423004155
1990	346049.341745709
1991	205849.995196145
1992	44591.1021897928
1993	150701.113633521
1994	53947.4135106579
1995	76024.0190037454
1996	28535.8667363906
1997	0
1998	0
1999	0
2000	0
2001	0
2002	0
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0
2009	0
2010	0
2011	0
2012	0
2013	0
2014	0
2015	0
2016	0
2017	0
2018	0
2019	0
2020	0
2021	0