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 | 3 | Metric tons | 0.00% |
| 2004 | 3 | Metric tons | 0.00% |
| 2005 | 2.59999990463257 | Metric tons | -13.33% |
| 2006 | 2.43700003623962 | Metric tons | -6.27% |
| 2007 | 2.40499997138977 | Metric tons | -1.31% |
| 2008 | 2 | Metric tons | -16.84% |
| 2009 | 1.70000004768372 | Metric tons | -15.00% |
| 2010 | 0.630999982357025 | Metric tons | -62.88% |
| 2011 | 0.649999976158142 | Metric tons | 3.01% |
| 2012 | 0.649999976158142 | Metric tons | 0.00% |
