Year	current US$
1960	20000000
1961	25000000
1962	12000000
1963	12000000
1964	7000000
1965	9000000
1966	10000000
1967	10000000
1968	10000000
1969	13000000
1970	18000000
1971	33000000
1972	49000000
1973	116000000
1974	393000000
1975	765000000
1976	725000000
1977	875000000
1978	947000000
1979	1246000000
1980	1732000000
1981	2413000000
1982	2868000000
1983	2623000000
1984	2933000000
1985	3364000000
1986	2565000000
1987	1965000000
1988	2342000000
1989	2364000000
1990	2798000000
1991	3327000000
1992	3902000000
1993	4296000000
1994	4014000000
1995	4379000000
1996	4728000000
1997	5191000000
1998	5826000000
1999	4801000000
2000	5131000000
2001	5933000000
2002	6296000000
2003	6801000000
2004	8796000000
2005	8971000000
2006	11039000000
2007	16025000000
2008	23137000000
2009	17936000000
2010	19973000000
2011	24019000000
2012	28636000000
2013	34331000000
2014	29303000000
2015	29007000000
2016	23148000000
2017	26435000000
2018	25770000000
2019	23507000000
2020	28507000000
2021	30995000000
2022	38573000000
2023	36382000000
