Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 23 | Metric tons | NA |
| 2003 | 23 | Metric tons | 0.00 % |
| 2004 | 25 | Metric tons | 8.70 % |
| 2005 | 25 | Metric tons | 0.00 % |
| 2006 | 25 | Metric tons | 0.00 % |
| 2007 | 26 | Metric tons | 4.00 % |
| 2008 | 25 | Metric tons | -3.85 % |
| 2009 | 25 | Metric tons | 0.00 % |
