Year	constant 2015 US$
1998	22651.246380415992
1999	22355.802203893756
2000	22480.96348513805
2001	23491.92770664371
2002	24354.108227436467
2003	25637.608115233852
2004	27884.97708927362
2005	29605.970852260136
2006	32480.802914228312
2007	35912.746435108405
2008	39096.941782924536
2009	40186.81247026452
2010	39695.276847285786
2011	35314.75061756948
2012	34223.20181369008
2013	32611.54568085
2014	31990.956530949094
2015	31472.888261817465
2016	32428.524433733637
2017	33343.29349018049
2018	35072.539417315136
2019	36503.85616139459
2020	37253.66883589053
2021	40393.83211861603
2022	40618.060514446894