Year	current US$
2000	7.491828233618174
2001	8.784827585215387
2002	8.498754785354096
2003	10.567983876977953
2004	13.649770444090057
2005	16.090540436397067
2006	18.09869181936423
2007	21.843592705288494
2008	25.215356786134766
2009	22.916629601320953
2010	23.547895434816187
2011	24.465976537370526
2012	23.140070483875938
2013	22.981943352952115
2014	21.493722267457514
2015	17.32779963408222
2016	20.34839071307853
2017	19.015919540322766
2018	23.76567067589958
2019	22.50496856742043
2020	23.536812969491177
2021	25.696282087157858