Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 2653 | Metric tons | NA |
| 2004 | 2720 | Metric tons | 2.53% |
| 2005 | 2700 | Metric tons | -0.74% |
| 2006 | 2750 | Metric tons | 1.85% |
| 2007 | 7532 | Metric tons | 173.89% |
