Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2008 | 2.5 | Metric tons | NA |
| 2009 | 2.59999990463257 | Metric tons | 4.00% |
| 2010 | 2.70000004768372 | Metric tons | 3.85% |
| 2011 | 2.59999990463257 | Metric tons | -3.70% |
| 2012 | 2.5 | Metric tons | -3.85% |
