Year	current US$
1997	15000000
1998	13000000
1999	5000000
2000	19000000
2001	29000000
2002	40000000
2003	40000000
2004	49000000
2005	68000000
2006	90000000
2007	101000000
2008	134000000
2009	130000000
2010	130000000
2011	171000000
2012	215000000
2013	243000000
2014	264000000
2015	279000000
2016	320000000
2017	389000000
2018	435000000
2019	467000000
2020	112000000