Year	current US$
2000	6.361571922612843
2001	2.2056063286127583
2002	5.754391448407969
2003	6.901135249110425
2004	8.371584569048235
2005	9.365286091248683
2006	15.664333964605458
2007	16.26519996231286
2008	18.111929527199457
2009	18.596762169551535
2010	19.131293175434504
2011	17.089351311525686
2012	9.321949454113174
2013	10.198856744315218
2014	11.35292278105351
2015	7.806145036773338
2016	8.652229587853814
2017	7.8547778170567994
2018	7.549139027654499
2019	6.801784525165658
2020	11.453263215011507
2021	13.480177126477976