Year	constant 2015 US$
2006	19137.94281695511
2007	19542.542439170273
2008	19131.539099342663
2009	18301.158592335752
2010	17206.257545145352
2011	15117.030818850864
2012	14590.73056428766
2013	14270.106588750343
2014	14757.45060040356
2015	15044.374439370613
2016	15089.970701472663
2017	15329.820988557007
2018	15449.141505233287
2019	15887.849938194076
2020	14364.772914706185
2021	15804.344905479245