Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2008 | 11000 | Metric tons | NA |
| 2009 | 11300 | Metric tons | 2.73% |
| 2010 | 11300 | Metric tons | 0.00% |
| 2011 | 11000 | Metric tons | -2.65% |
| 2012 | 11000 | Metric tons | 0.00% |
