Year	current US$
2000	6.985146329720294
2001	7.099289002259406
2002	7.342940220894972
2003	8.638578335081851
2004	10.333768110543277
2005	10.932322872502919
2006	12.66112438020388
2007	14.545372223811393
2008	15.099703543590202
2009	18.036003197890484
2010	17.886572976130104
2011	20.94089713188763
2012	21.77529069569819
2013	20.823749621450215
2014	20.569883728669883
2015	20.351257758689833
2016	20.829816905538696
2017	18.080398365709925
2018	23.867434956867516
2019	25.116496250285888
2020	23.544273416155633
2021	23.94890732283394