Year	constant 2015 US$
1990	358.947174072266
1991	356.712005615234
1992	348.338287353516
1993	343.616394042969
1994	335.841094970703
1995	339.2294921875
1996	356.744354248047
1997	379.946502685547
1998	422.818572998047
1999	431.833435058594
2000	424.870727539063
2001	425.576049804688
2002	438.684844970703
2003	435.471832275391
2004	449.430572509766
2005	474.542205810547
2006	504.789367675781
2007	517.824951171875
2008	504.058441162109
2009	495.13134765625
2010	547.589233398438
2011	591.629943847656
2012	558.17626953125
2013	565.657165527344
2014	577.704040527344
2015	593.787536621094
2016	580.009582519531
2017	584.352416992188
2018	601.222045898438
2019	601.707275390625
2020	589.468627929688
2021	585.259643554688
2022	594.435119628906
2023	591.261352539063