Year	current US$
2000	2.5333626178549555
2001	2.3155143760888413
2002	2.65663978493277
2003	2.904287043619342
2004	3.9697253975675846
2005	4.928483827661975
2006	6.22836039523072
2007	6.688328841655429
2008	7.944555367165479
2009	8.908765170058802
2010	9.619115291295142
2011	11.568546578394715
2012	11.33393692272326
2013	11.883701901398432
2014	11.744265195559676
2015	10.642421662076597
2016	10.014897410088386
2017	10.287589041511415
2018	10.823851109762753
2019	10.997297605029305
2020	10.439059211657026
2021	12.309657507616626