Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 10500 | Metric tons | NA |
| 2004 | 10500 | Metric tons | 0.00% |
| 2005 | 38000 | Metric tons | 261.90% |
| 2006 | 40000 | Metric tons | 5.26% |
| 2007 | 42000 | Metric tons | 5.00% |
| 2008 | 38000 | Metric tons | -9.52% |
| 2009 | 35000 | Metric tons | -7.89% |
