Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 27 | Metric tons | NA |
| 2003 | 27 | Metric tons | 0.00% |
| 2004 | 28 | Metric tons | 3.70% |
| 2005 | 28 | Metric tons | 0.00% |
| 2006 | 28.1000003814697 | Metric tons | 0.36% |
| 2007 | 10 | Metric tons | -64.41% |
| 2008 | 19.9540004730225 | Metric tons | 99.54% |
| 2009 | 20.3969993591309 | Metric tons | 2.22% |
| 2010 | 19.6410007476807 | Metric tons | -3.71% |
| 2011 | 19.1070003509521 | Metric tons | -2.72% |
| 2012 | 19.1180000305176 | Metric tons | 0.06% |
