Year	current US$
1960	8000000
1961	7000000
1962	7000000
1963	7000000
1964	9000000
1965	9000000
1966	9000000
1967	9000000
1968	10000000
1969	12000000
1970	15000000
1971	18000000
1972	18000000
1973	19000000
1974	25000000
1975	25000000
1976	24000000
1977	30000000
1978	36000000
1979	47000000
1980	57000000
1981	58000000
1982	65000000
1983	70000000
1984	77000000
1985	79000000
1986	87000000
1987	99000000
1988	122000000
1989	127000000
1990	136000000
1991	140000000
1992	132000000
1993	134000000
1994	130000000
1995	136000000
1996	132000000
1997	188000000
1998	193000000
1999	201000000
2000	163000000
2001	186000000
2002	174000000
2003	201000000
2004	226000000
2005	240000000
2006	271000000
2007	327000000
2008	373000000
2009	333000000
2010	338000000
2011	332000000
2012	356000000
2013	370000000
2014	361000000
2015	334000000
2016	335000000
2017	330000000
2018	354000000
2019	335000000
2020	321000000
2021	373000000
2022	438000000
2023	414000000