Year	current US$
1977	303798748.7563677
1978	131739520.74364285
1979	-64878372.782240905
1980	-108178949.45952868
1981	174730066.08882624
1982	-467273582.8680994
1983	-601675587.1497359
1984	359810897.69140136
1985	235627910.39285815
1986	136610393.17475462
1987	-128133771.30725268
1988	241567309.71972924
1989	75236045.09322263
1990	-107362549.24935056
1991	-490206430.973644
1992	-782170768.088802
1993	-10078885.505216002
1994	-364218404.2951247
2009	-638106118.0673399
2010	-177158808.98521996
2011	-35316080.94517994
2012	-2167357346.6553802
2013	-1046477152.4718499
2014	-933990325.33182
2015	-2013648230.24155
2016	-1020820872.58111
2017	-471700088.58983356
2018	4755859186.2208
2019	3866314688.3326755
2020	3605388886.1695714