Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 5000 | Metric tons | NA |
| 2004 | 5000 | Metric tons | 0.00% |
| 2005 | 5000 | Metric tons | 0.00% |
| 2006 | 5500 | Metric tons | 10.00% |
| 2007 | 5500 | Metric tons | 0.00% |
| 2008 | 6000 | Metric tons | 9.09% |
| 2009 | 6000 | Metric tons | 0.00% |
| 2010 | 6500 | Metric tons | 8.33% |
| 2011 | 6500 | Metric tons | 0.00% |
| 2012 | 7000 | Metric tons | 7.69% |
| 2013 | 6000 | Metric tons | -14.29% |
