Year	current US$
2000	10.16078309
2001	9.446091
2002	10.39294817
2003	12.17449248
2004	12.82381599
2005	14.50505267
2006	16.17870508
2007	19.22489311
2008	22.22321776
2009	22.65452464
2010	18.79132896
2011	17.04197056
2012	13.37477219
2013	11.54592084
2014	13.11577367
2015	10.80562292
2016	10.68281459
2017	11.49721823
2018	10.91941194
2019	17.62855757
2020	15.51199711
2021	16.44954154