Year	current US$
1972	2082634.7305389221
1973	2980453.702382651
1974	5139638.582492373
1975	2644425.5640022987
1976	2712994.5104633598
1977	2479416.7382807084
1978	9358342.328070791
1979	6230432.095108541
1980	9250276.688482929
1981	14558471.182408946
1982	18778471.24803345
1983	17463727.967640076
1984	13985725.556133773
1985	12248803.159449542
1986	15059085.251481645
1987	17504796.31419009
1988	18907608.984395754
1989	18037366.84493163
1990	26462522.744889572
1991	21772050.140369356
1992	19094509.00673302
2006	15180504.422906188
2007	17853903.363144647
2008	17414513.604512077
2009	21596270.12866278
2010	22378111.81671664
2011	33061292.69502807
2012	52334280.043197304
2013	58831888.61632506
2014	53788705.770789176
2015	71265353.95803438
2016	60667596.38243432
2017	56251580.7529059
2018	45383857.88531484
2019	33070746.26678911
2020	32243055.29270483
2021	47765516.52455101