Year	current US$
2000	34.39358384
2001	28.85408276
2002	24.52079144
2003	35.54568048
2004	43.30089925
2005	45.74907502
2006	44.67967366
2007	44.6355227
2008	39.51919782
2009	39.97652327
2010	50.21927928
2011	53.79910688
2012	50.52167386
2013	45.86395585
2014	31.02923814
2015	28.64543601
2016	26.80686809
2017	31.31903673
2018	33.27179746
2019	31.587744
2020	26.51828824
2021	32.14123071