Year	current US$
2000	258.19668054
2001	246.83265035
2002	262.08358635
2003	268.34513747
2004	248.78630617
2005	293.046288
2006	378.23440243
2007	396.45213598
2008	549.01809729
2009	522.39127847
2010	521.88801875
2011	555.79906706
2012	527.63044395
2013	570.56262566
2014	559.87787684
2015	638.13573692
2016	685.13676199
2017	682.24509339
2018	596.18323716
2019	611.13688269
2020	485.24633045
2021	473.77531858