Year	current US$
1960	4000000
1961	3000000
1962	2000000
1963	2000000
1964	3000000
1965	3000000
1966	4000000
1967	4000000
1968	4000000
1969	4000000
1970	3000000
1971	2000000
1972	3000000
1973	5000000
1974	7000000
1975	6000000
1976	4000000
1977	7000000
1978	5000000
1979	7000000
1980	7000000
1981	8000000
1982	8000000
1983	5000000
1984	9000000
1985	5000000
1986	6000000
1987	6000000
1988	8000000
1989	9000000
1990	11000000
1991	13000000
1992	12000000
1993	16000000
1994	14000000
1995	14000000
1996	11000000
1997	10000000
1998	7000000
1999	12000000
2000	9000000
2001	7000000
2002	15000000
2003	18000000
2004	15000000
2005	10000000
2006	10000000
2007	8000000
2008	9000000
2009	8000000
2010	8000000
2011	14000000
2012	16000000
2013	17000000
2014	19000000
2015	18000000
2016	21000000
2017	19000000
2018	13000000
2019	20000000
2020	15000000
2021	16000000
2022	13000000
2023	9000000