Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 3 | Metric tons | NA |
| 2003 | 2.24600005149841 | Metric tons | -25.13 % |
| 2004 | 4 | Metric tons | 78.09 % |
| 2005 | 2.74900007247925 | Metric tons | -31.28 % |
| 2006 | 2.36899995803833 | Metric tons | -13.82 % |
| 2007 | 3.40000009536743 | Metric tons | 43.52 % |
| 2008 | 3.45000004768372 | Metric tons | 1.47 % |
| 2009 | 3.5 | Metric tons | 1.45 % |
