Year	current US$
2000	4.93588482
2001	5.19314685
2002	5.75862563
2003	6.21059939
2004	4.45624266
2005	5.37079894
2006	5.30648887
2007	6.43873334
2008	7.9351382
2009	7.51915051
2010	7.80116383
2011	6.53798903
2012	6.40630279
2013	7.03191232
2014	6.49999467
2015	5.74204896
2016	5.71265155
2017	6.19824406
2018	6.34580393
2019	5.43737584
2020	5.32637473
2021	5.77035161