Year	current US$
1960	4000000
1961	4000000
1962	5000000
1963	5000000
1964	6000000
1965	7000000
1966	6000000
1967	6000000
1968	5000000
1969	7000000
1970	6000000
1971	4000000
1972	8000000
1973	13000000
1974	14000000
1975	12000000
1976	17000000
1977	14000000
1978	32000000
1979	45000000
1980	58000000
1981	50000000
1982	37000000
1983	31000000
1984	29000000
1985	23000000
1986	26000000
1987	47000000
1988	64000000
1989	66000000
1990	62000000
1991	67000000
1992	109000000
1993	133000000
1994	143000000
1995	160000000
1996	187000000
1997	196000000
1998	194000000
1999	172000000
2000	220000000
2001	280000000
2002	358000000
2003	476000000
2004	708000000
2005	651000000
2006	718000000
2007	830000000
2008	884000000
2009	734000000
2010	878000000
2011	1172000000
2012	972000000
2013	847000000
2014	826000000
2015	929000000
2016	881000000
2017	1028000000
2018	1221000000
2019	919000000
2020	845000000
2021	935000000
2022	894000000
2023	794000000