Year	current US$
2000	1.77872683
2001	1.65211509
2002	2.00924255
2003	2.32416827
2004	2.06584383
2005	2.26679353
2006	3.83194122
2007	5.34476957
2008	6.73209279
2009	7.12557789
2010	5.2132953
2011	5.5161148
2012	4.37285477
2013	5.47395698
2014	5.07253765
2015	6.29645824
2016	7.39940115
2017	6.62989961
2018	6.7008841
2019	7.20724273
2020	9.45897601
2021	9.25365274