Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 2450 | Metric tons | NA |
| 2004 | 2450 | Metric tons | 0.00% |
| 2005 | 2150 | Metric tons | -12.24% |
| 2006 | 2470 | Metric tons | 14.88% |
| 2007 | 2500 | Metric tons | 1.21% |
| 2008 | 2500 | Metric tons | 0.00% |
