Year	current US$
2000	4.09642305
2001	4.2715052
2002	4.83598188
2003	4.8762884
2004	5.41340693
2005	4.60369083
2006	4.79852763
2007	6.0937531
2008	6.89677514
2009	6.34435927
2010	8.37347951
2011	7.50490046
2012	8.34868601
2013	8.93045063
2014	9.09352759
2015	6.08510735
2016	6.13544359
2017	5.02771541
2018	5.53423091
2019	5.04973068
2020	8.05820931
2021	9.78984207