Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 14 | Metric tons | NA |
| 2003 | 13 | Metric tons | -7.14% |
| 2004 | 14 | Metric tons | 7.69% |
| 2005 | 13.5010004043579 | Metric tons | -3.56% |
| 2006 | 9.10000038146973 | Metric tons | -32.60% |
| 2007 | 9.02799987792969 | Metric tons | -0.79% |
| 2008 | 8.23200035095215 | Metric tons | -8.82% |
| 2009 | 8.52700042724609 | Metric tons | 3.58% |
| 2010 | 7.67000007629395 | Metric tons | -10.05% |
| 2011 | 7.90000009536743 | Metric tons | 3.00% |
| 2012 | 4 | Metric tons | -49.37% |
