Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1095 | Metric tons | NA |
| 2004 | 1042 | Metric tons | -4.84% |
| 2005 | 1131 | Metric tons | 8.54% |
| 2006 | 1150 | Metric tons | 1.68% |
| 2007 | 1150 | Metric tons | 0.00% |
| 2008 | 1150 | Metric tons | 0.00% |
| 2009 | 1150 | Metric tons | 0.00% |
| 2010 | 1150 | Metric tons | 0.00% |
| 2011 | 1150 | Metric tons | 0.00% |
| 2012 | 1150 | Metric tons | 0.00% |
| 2013 | 1150 | Metric tons | 0.00% |
