Year	current US$
1960	8000000
1961	9000000
1962	9000000
1963	11000000
1964	12000000
1965	14000000
1966	15000000
1967	13000000
1968	10000000
1969	18000000
1970	26000000
1971	42000000
1972	58000000
1973	85000000
1974	121000000
1975	142000000
1976	170000000
1977	186000000
1978	233000000
1979	451000000
1980	502000000
1981	397000000
1982	454000000
1983	635000000
1984	660000000
1985	728000000
1986	862000000
1987	1587000000
1988	1465000000
1989	1857000000
1990	1784000000
1991	1849000000
1992	1742000000
1993	1780000000
1994	1878000000
1995	2142000000
1996	2447000000
1997	2842000000
1998	2058000000
1999	2644000000
2000	2675000000
2001	2510000000
2002	2425000000
2003	2810000000
2004	3513000000
2005	4425000000
2006	4529000000
2007	5174000000
2008	4951000000
2009	3456000000
2010	4693000000
2011	5882000000
2012	5971000000
2013	7911000000
2014	8510000000
2015	6316000000
2016	7366000000
2017	5870000000
2018	6575000000
2019	5237000000
2020	4262000000
2021	7420000000
2022	8314000000
2023	5424000000