Year	current US$
1992	16000000
1993	42000000
1994	78000000
1995	86000000
1996	98000000
1997	57000000
1998	28000000
1999	21000000
2000	37000000
2001	19000000
2002	52000000
2003	7000000
2004	11000000
2005	11000000
2006	12000000
2007	13000000
2008	11000000
2009	11000000
2010	13000000
2011	430000000
2012	480000000
2013	316000000
2014	630000000
2015	499000000
2016	436000000
2017	583000000
2018	669000000
2019	530000000
2020	306000000
2021	489000000
2022	579000000
2023	495000000