Year	current US$
2000	296.76438365
2001	297.06720739
2002	303.44523397
2003	336.24926623
2004	369.74755775
2005	399.30127078
2006	433.36031886
2007	454.40205458
2008	472.62780452
2009	489.16141632
2010	494.34491773
2011	565.68554125
2012	575.07764087
2013	584.43286706
2014	596.8482658
2015	596.88602396
2016	619.62903811
2017	628.02366984
2018	625.57573555
2019	635.82139044
2020	617.52190446
2021	633.01144718