Year	current US$
1975	13879862.5156108
1976	16693968.4819117
1977	45192562.3234359
1978	96399317.1994034
1979	83181560.7765114
1980	185406268.319665
1981	132560539.770388
2007	685833972.189651
2008	713324263.608521
2009	421056311.789604
2010	208691804.344415
2011	3562538.11575347
2012	121940696.300386
2013	260753355.999592
2014	385765452.691988
2015	371060535.211218
2016	143242293.069969
2017	-69911265.1306564
2018	86589510.3312956
2019	84159813.4084159
2020	159432831.848973