Year	current US$
1960	4000000
1961	3000000
1962	4000000
1963	5000000
1964	4000000
1965	6000000
1966	6000000
1967	5000000
1968	5000000
1969	8000000
1970	6000000
1971	5000000
1972	5000000
1973	7000000
1974	10000000
1975	12000000
1976	13000000
1977	14000000
1978	17000000
1979	21000000
1980	17000000
1981	19000000
1982	19000000
1983	19000000
1984	18000000
1985	23000000
1986	31000000
1987	32000000
1988	33000000
1989	28000000
1990	27000000
1991	23000000
1992	20000000
1993	20000000
1994	23000000
1995	22000000
1996	20000000
1997	23000000
1998	35000000
1999	36000000
2000	48000000
2001	43000000
2002	38000000
2003	42000000
2004	32000000
2005	28000000
2006	25000000
2007	33000000
2008	31000000
2009	29000000
2010	25000000
2011	31000000
2012	35000000
2013	37000000
2014	37000000
2015	33000000
2016	30000000
2017	30000000
2018	31000000
2019	34000000
2020	25000000
2021	35000000
2022	37000000
2023	46000000