Year	current US$
1988	157.380661010742
1989	133.230361938477
1990	123.872360229492
1991	141.8857421875
1992	125.62109375
1993	110.828475952148
1994	115.678344726563
1995	132.752212524414
1996	166.440216064453
1997	197.469375610352
1998	315.954040527344
1999	322.906066894531
2000	333.656433105469
2001	328.0361328125
2002	342.091674804688
2003	358.487396240234
2004	384.937225341797
2005	416.026031494141
2006	417.683410644531
2007	468.028839111328
2008	580.059875488281
2009	569.196044921875
2010	586.049255371094
2011	593.00048828125
2012	624.233764648438
2013	739.359741210938
2014	812.667602539063
2015	768.614624023438
2016	786.23193359375
2017	828.0517578125
2018	884.947631835938
2019	942.602661132813
2020	927.706909179688
2021	960.039123535156