Year	constant 2015 US$
1995	20703.850537155256
1996	21454.61738972869
1997	21870.406911310012
1998	22415.20380436696
1999	22246.000816728643
2000	23057.341981716243
2001	23008.237476713126
2002	22354.174461948416
2003	22058.616390527237
2004	22626.37117936418
2005	23517.88413850016
2006	24567.632042255467
2007	25581.73343482916
2008	25298.374465973386
2009	25420.286279137064
2010	26612.95412810776
2011	27462.273723682858
2012	27414.78835244376
2013	28666.17924606364
2014	29775.353937163418
2015	30461.96240809489
2016	31556.625029083876
2017	32522.658399813005
2018	33055.96216312645
2019	34117.39369611946
2020	32697.025397073576
2021	35101.81728266734