Year	constant 2010 US$
2006	245.049621514177
2007	241.028762314021
2008	244.29128261341
2009	247.707577090646
2010	250.741057775065
2011	254.05714719204
2012	254.604355386925
2013	254.806935824489
2014	253.81264317952
2015	261.490669715182
2016	265.531626719389
2017	267.117478295779