Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 1 | Metric tons | NA |
| 2003 | 1 | Metric tons | 0.00 % |
| 2004 | 1 | Metric tons | 0.00 % |
| 2005 | 0.885999977588654 | Metric tons | -11.40 % |
| 2006 | 0.90200001001358 | Metric tons | 1.81 % |
| 2007 | 0.707000017166138 | Metric tons | -21.62 % |
| 2008 | 1.02600002288818 | Metric tons | 45.12 % |
| 2009 | 1 | Metric tons | -2.53 % |
