Year	current US$
1960	8000000
1961	8000000
1962	6000000
1963	7000000
1964	7000000
1965	8000000
1966	7000000
1967	8000000
1968	9000000
1969	1000000
1970	6000000
1971	10000000
1972	16000000
1973	20000000
1974	20000000
1975	28000000
1976	25000000
1977	31000000
1978	34000000
1979	25000000
1980	61000000
1981	77000000
1982	60000000
1983	39000000
1984	92000000
1985	13000000
1986	22000000
1987	32000000
1988	45000000
1989	63000000
1990	82000000
1991	73000000
1992	77000000
1993	106000000
1994	85000000
1995	85000000
1996	73000000
1997	89000000
1998	86000000
1999	76000000
2000	74000000
2001	61000000
2002	50000000
2003	43000000
2004	53000000
2005	52000000
2006	53000000
2007	91000000
2008	105000000
2009	51000000
2010	46000000
2011	43000000
2012	46000000
2013	45000000
2014	41000000
2015	32000000
2016	33000000
2017	33000000
2018	34000000
2019	32000000
2020	36000000
2021	44000000
2022	33000000
2023	23000000