Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 80 | Metric tons | NA |
| 2003 | 80 | Metric tons | 0.00% |
| 2004 | 80 | Metric tons | 0.00% |
| 2005 | 83 | Metric tons | 3.75% |
| 2006 | 83 | Metric tons | 0.00% |
| 2007 | 83 | Metric tons | 0.00% |
| 2008 | 74.6480026245117 | Metric tons | -10.06% |
| 2009 | 52.8759994506836 | Metric tons | -29.17% |
| 2010 | 59.0970001220703 | Metric tons | 11.77% |
| 2011 | 60 | Metric tons | 1.53% |
| 2012 | 63 | Metric tons | 5.00% |
