Year	current US$
1960	8000000
1961	9000000
1962	10000000
1963	9000000
1964	9000000
1965	14000000
1966	16000000
1967	18000000
1968	13000000
1969	16000000
1970	17000000
1971	13000000
1972	19000000
1973	25000000
1974	43000000
1975	44000000
1976	35000000
1977	47000000
1978	39000000
1979	58000000
1980	31000000
1981	27000000
1982	44000000
1983	48000000
1984	49000000
1985	43000000
1986	35000000
1987	40000000
1988	58000000
1989	27000000
1990	31000000
1991	38000000
1992	57000000
1993	67000000
1994	35000000
1995	16000000
1996	21000000
1997	15000000
1998	21000000
1999	12000000
2000	16000000
2001	9000000
2002	17000000
2003	5000000
2004	18000000
2005	7000000
2006	11000000
2007	13000000
2008	14000000
2009	66000000
2010	68000000
2011	102000000
2012	126000000
2013	134000000
2014	125000000
2015	115000000
2016	105000000
2017	124000000
2018	140000000
2019	133000000
2020	61000000
2021	33000000
2022	40000000
2023	40000000