Year	current US$
1960	4000000
1961	3000000
1962	3000000
1963	2000000
1964	2000000
1965	2000000
1966	2000000
1967	3000000
1968	2000000
1969	3000000
1970	2000000
1971	4000000
1972	5000000
1973	7000000
1974	7000000
1975	7000000
1976	6000000
1977	10000000
1978	14000000
1979	21000000
1980	29000000
1981	31000000
1982	43000000
1983	57000000
1984	53000000
1985	53000000
1986	45000000
1987	81000000
1988	90000000
1989	113000000
1990	138000000
1991	161000000
1992	189000000
1993	191000000
1994	222000000
1995	268000000
1996	302000000
1997	349000000
1998	354000000
1999	402000000
2000	389000000
2001	393000000
2002	392000000
2003	471000000
2004	642000000
2005	745000000
2006	927000000
2007	1096000000
2008	1388000000
2009	963000000
2010	1091000000
2011	1465000000
2012	1554000000
2013	1733000000
2014	1993000000
2015	1896000000
2016	2125000000
2017	2360000000
2018	2960000000
2019	2888000000
2020	1838000000
2021	2573000000
2022	3516000000
2023	3497000000