Year	constant 2015 US$
1989	24204.67520048749
1990	23316.618598960522
1991	21302.830807377097
1992	20995.24967244375
1993	20014.37222829411
1994	19940.91909216634
1995	24144.188561818988
1996	26862.774923855606
1997	28949.439573386862
1998	30758.648404074465
1999	33437.44901433885
2000	34388.34335562585
2001	33012.71650452063
2002	36122.50055061977
2003	34878.70937776419
2004	33431.12484487599
2005	34533.363022988844
2006	33010.44032892006
2007	33987.431338015456
2008	32446.78408183085
2009	28925.653483806378
2010	27703.695156688827
2011	26843.585554871082
2012	26548.03943321786
2013	25570.807302384215
2014	26002.01757377503
2015	26400.91532746367
2016	26255.403766635867
2017	27539.58552915383
2018	26875.080771689354
2019	27265.318241881476
2020	19996.527011801616
2021	22541.792752458645