Year	PPG (TDS, current US$)
2008	684816997.4
2009	618317153.1
2010	619964955.1
2011	618814603.7
2015	0
2016	47588.2
2017	316324.5
2018	19776490
2019	661701.4
2020	2351.5
2021	0
2022	0