Year	current US$
2000	4.52402995
2001	6.43984103
2002	4.77020622
2003	6.76456468
2004	6.69707116
2005	16.0401065
2006	18.40836551
2007	23.65898926
2008	27.94790783
2009	30.49396967
2010	40.16014435
2011	48.16406981
2012	41.07640969
2013	42.41055395
2014	27.37249348
2015	27.27385718
2016	24.71264029
2017	30.22240163
2018	38.17044342
2019	49.97910718
2020	45.95237863
2021	54.05580119