Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 127300 | Metric tons | NA |
| 2010 | 67000 | Metric tons | -47.37% |
| 2011 | 119800 | Metric tons | 78.81% |
| 2012 | 129000 | Metric tons | 7.68% |
| 2013 | 80000 | Metric tons | -37.98% |
