Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 161 | Metric tons | NA |
| 2003 | 150 | Metric tons | -6.83% |
| 2004 | 150 | Metric tons | 0.00% |
| 2005 | 140 | Metric tons | -6.67% |
| 2006 | 140 | Metric tons | 0.00% |
| 2007 | 145 | Metric tons | 3.57% |
| 2008 | 150 | Metric tons | 3.45% |
| 2009 | 150 | Metric tons | 0.00% |
