Year	current US$
2000	5.513487478180755
2001	5.427511124446679
2002	8.001141474906301
2003	8.231981664465538
2004	11.431486631544436
2005	13.396227496594207
2006	16.40370005122614
2007	15.940850803355382
2008	17.452019153421052
2009	18.167203382816233
2010	21.140374037328858
2011	23.8632966577102
2012	21.355738858118187
2013	22.38650363099907
2014	22.794703704826695
2015	19.789596449280797
2016	17.766343080023677
2017	16.192185855163025
2018	17.176089453666897
2019	17.38716060452609
2020	18.39052824146833
2021	30.219677873393106