Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 5695 | Metric tons, gross weight | NA |
| 2003 | 1924 | Metric tons, gross weight | -66.22% |
| 2004 | 1784 | Metric tons, gross weight | -7.28% |
| 2005 | 867 | Metric tons, gross weight | -51.40% |
| 2006 | 19 | Metric tons, gross weight | -97.81% |
