Year	current US$
2000	1.78843821
2001	1.62181477
2002	1.80786334
2003	1.94147604
2004	2.19322266
2005	2.26640101
2006	2.4496763
2007	2.59813572
2008	3.03566749
2009	3.82188951
2010	4.86508028
2011	6.46866959
2012	6.52443437
2013	5.07946272
2014	5.34213895
2015	5.62884586
2016	5.51520126
2017	5.00631124
2018	5.7072378
2019	5.74610148
2020	5.86953512
2021	6.35915384