Year	current US$
2000	4.68923706
2001	4.23804301
2002	4.69602395
2003	4.23642936
2004	4.84376867
2005	2.56065618
2006	2.66297218
2007	4.23468801
2008	4.55449375
2009	4.3378527
2010	5.18575441
2011	4.962985
2012	5.49871185
2013	4.63234955
2014	4.02888613
2015	4.46317977
2016	4.73763822
2017	5.64613142
2018	3.75059731
2019	4.44848343
2020	4.95900001
2021	5.37712328