Year	current US$
2000	5.32821401
2001	5.53829215
2002	5.90181893
2003	6.49709536
2004	7.00975954
2005	7.59714967
2006	8.12547736
2007	9.57300866
2008	10.85002463
2009	12.36967899
2010	14.37294092
2011	15.87543039
2012	16.3166329
2013	19.08144347
2014	21.43688837
2015	24.37396736
2016	28.28283014
2017	29.63203803
2018	31.6252692
2019	34.34476444
2020	37.49246151
2021	42.28789497