Year	current US$
2000	2.19309952
2001	2.36695053
2002	2.29220345
2003	2.67679452
2004	1.78210412
2005	2.76321569
2006	2.14376538
2007	3.14234038
2008	1.58841288
2009	2.99688777
2010	2.8332037
2011	1.26533198
2012	4.7667972
2013	5.27180309
2014	3.88137549
2015	5.94277559
2016	6.16791829
2017	6.1129363
2018	5.53186576
2019	5.92812411
2020	8.10198233
2021	8.0810863