Year	constant 2015 US$
1997	4488.794625121975
1998	4723.143383584753
1999	4290.896849413425
2000	4431.600470144192
2001	4462.349901178838
2002	4529.123305729946
2003	4623.076064461499
2004	4819.1478598860795
2005	5013.195900992096
2006	5435.8862210362695
2007	5798.064973334474
2008	6205.821247209498
2009	5833.659544189039
2010	5982.199284660658
2011	6168.848386374152
2012	5995.77445120446
2013	6202.506702947854
2014	6307.018561291743
2015	6517.192675147636
2016	6707.8504102082425
2017	7023.433811812459
2018	7381.807640329365
2019	7684.183971971851
2020	6515.536805604512
2021	7390.308117278318
2022	7889.237633106137
2023	8375.22211138647