Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 8000 | Metric tons, gross weight | NA |
| 2003 | 10000 | Metric tons, gross weight | 25.00% |
| 2004 | 7750 | Metric tons, gross weight | -22.50% |
| 2005 | 8000 | Metric tons, gross weight | 3.23% |
| 2006 | 8000 | Metric tons, gross weight | 0.00% |