Year	constant 2015 US$
1997	651.9423602927495
1998	494.35467201592854
1999	566.2586165581853
2000	556.8814347614467
2001	572.749347625235
2002	585.4967504119338
2003	572.1517520480548
2004	564.6520036361532
2005	589.4791191073281
2006	590.5297515902249
2007	590.6371851615958
2008	600.0131249034005
2009	601.2350378392244
2010	624.1361596359076
2011	648.8164200179691
2012	612.3872646889879
2013	629.3822714678176
2014	641.316541999164
2015	658.4734496335747
2016	670.8478131072313
2017	683.3734453633219
2018	662.6604354121416
2019	712.2578911163495
2020	705.8078034430088
2021	729.6532857913182
2022	747.6256566437977
2023	762.1979689659566