Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 277 | Metric tons | NA |
| 2003 | 201 | Metric tons | -27.44% |
| 2004 | 186 | Metric tons | -7.46% |
| 2005 | 196 | Metric tons | 5.38% |
| 2006 | 195 | Metric tons | -0.51% |
| 2007 | 195 | Metric tons | 0.00% |
| 2008 | 190 | Metric tons | -2.56% |
| 2009 | 195 | Metric tons | 2.63% |
| 2010 | 195 | Metric tons | 0.00% |
| 2011 | 190 | Metric tons | -2.56% |
| 2012 | 190 | Metric tons | 0.00% |
