Year	current US$
2000	17.35933149
2001	17.41611682
2002	17.64008634
2003	19.61877072
2004	21.59762128
2005	22.27373876
2006	23.43225291
2007	25.8867342
2008	29.56990444
2009	27.70073031
2010	27.18091986
2011	27.71934043
2012	27.17093635
2013	27.7884415
2014	28.27385843
2015	27.40821624
2016	26.26955935
2017	26.26666987
2018	27.16657507
2019	27.23486889
2020	27.50704746
2021	29.55307895