Year	current US$
2000	10.096420939860348
2001	9.354160667248523
2002	10.081724514379092
2003	11.404318611587312
2004	12.616489290367118
2005	13.552710304358405
2006	15.436933544696538
2007	18.06536186559042
2008	20.19976672693735
2009	19.334961120442358
2010	19.820133539694243
2011	21.340088365618783
2012	21.750346069213794
2013	24.394988507555773
2014	24.389489047115124
2015	23.683725310646185
2016	23.101816330988164
2017	21.98232794601721
2018	20.921779532008816
2019	21.404473160764542
2020	21.475292727157417
2021	22.751512185571023