Year	constant 2015 US$
1991	32430.070405571103
1992	32683.814724987627
1993	31947.319749891
1994	31178.71274713461
1995	29599.2908395408
1996	29274.662091291048
1997	29670.525869213005
1998	29431.268678919652
1999	29101.179945464333
2000	28225.901580296784
2001	28150.027296826498
2002	28036.74706786651
2003	27948.741710427992
2004	29686.939341153757
2005	30848.196395992127
2006	31895.113734227598
2007	32721.642133670823
2008	33630.32800743627
2009	34350.73488008839
2010	35153.31686540653
2011	36524.72740580196
2012	36869.98563584086
2013	37938.9074805997
2014	38886.398952822856
2015	38690.788247304656
2016	38104.51963646854
2017	39377.83279008581
2018	37148.50523940085
2019	35443.25326390292
2020	33547.69285614062
2021	32877.41624114388
2022	32488.723678381783