Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 477 | Metric tons | NA |
| 2004 | 489 | Metric tons | 2.52% |
| 2005 | 409 | Metric tons | -16.36% |
| 2006 | 457 | Metric tons | 11.74% |
| 2007 | 583 | Metric tons | 27.57% |
| 2008 | 599 | Metric tons | 2.74% |
| 2009 | 553 | Metric tons | -7.68% |
| 2010 | 550 | Metric tons | -0.54% |
| 2011 | 449 | Metric tons | -18.36% |
| 2012 | 450 | Metric tons | 0.22% |
| 2013 | 450 | Metric tons | 0.00% |
