Year	current US$
1991	138585000
1992	114731888.243437
1993	74836676.5151516
1994	88972662.7132866
1995	98916576.4300412
1996	85832188.1360563
1997	70411034.3939774
1998	70504368.655739
1999	44064805.7630464
2000	40175881.1397147
2001	49991158.2617221
2002	68105096.5706338
2003	80965552.7456435
2004	95135499.7836533
2005	113388675.62799
2006	144318368.459065
2007	214993391.6645
2008	262942639.964894
2009	268265404.235259
2010	260825877.931568
2011	395475040.88341
2012	461449723.301812
2013	439604954.845875
2014	358028387.943038
2015	337041257.325028
2016	368975487.275347
2017	395000653.414245
2018	400913446.174734
2019	427869228.40539
2020	397873590.735227
2021	414972631.588744