Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 4289 | Kilograms | NA |
| 2003 | 4739 | Kilograms | 10.49% |
| 2004 | 4221 | Kilograms | -10.93% |
| 2005 | 4250 | Kilograms | 0.69% |
| 2006 | 3497 | Kilograms | -17.72% |
| 2007 | 2913 | Kilograms | -16.70% |
| 2008 | 2489 | Kilograms | -14.56% |
| 2009 | 2794 | Kilograms | 12.25% |
| 2010 | 3766 | Kilograms | 34.79% |
| 2011 | 4219 | Kilograms | 12.03% |
| 2012 | 4624 | Kilograms | 9.60% |
