Year	current US$
2000	10.41100961
2001	8.97496065
2002	10.42471751
2003	11.70553153
2004	13.75061417
2005	17.12976741
2006	19.25466433
2007	20.48674632
2008	21.09134608
2009	21.46718203
2010	24.28701487
2011	24.49925459
2012	22.58649848
2013	22.03053307
2014	21.04011081
2015	19.04354242
2016	18.04431468
2017	19.74686339
2018	21.53759742
2019	21.65936308
2020	20.40422057
2021	21.8430991