Year	current US$
1960	3000000
1961	3000000
1962	4000000
1963	4000000
1964	4000000
1965	4000000
1966	4000000
1967	4000000
1968	4000000
1969	4000000
1970	4000000
1971	3000000
1972	3000000
1973	5000000
1974	7000000
1975	8000000
1976	9000000
1977	10000000
1978	16000000
1979	15000000
1980	15000000
1981	24000000
1982	32000000
1983	41000000
1984	54000000
1985	63000000
1986	64000000
1987	52000000
1988	85000000
1989	75000000
1990	83000000
1991	67000000
1992	78000000
1993	58000000
1994	50000000
1995	43000000
1996	46000000
1997	46000000
1998	50000000
1999	49000000
2000	47000000
2001	41000000
2002	38000000
2003	38000000
2004	37000000
2005	40000000
2006	38000000
2007	48000000
2008	52000000
2009	49000000
2010	42000000
2011	38000000
2012	43000000
2013	49000000
2014	48000000
2015	46000000
2016	47000000
2017	42000000
2018	44000000
2019	39000000
2020	55000000
2021	35000000
2022	46000000
2023	43000000