Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 3670 | Kilograms | NA |
| 2003 | 3875 | Kilograms | 5.59 % |
| 2004 | 3443 | Kilograms | -11.15 % |
| 2005 | 4376 | Kilograms | 27.10 % |
| 2006 | 4028 | Kilograms | -7.95 % |
| 2007 | 4368 | Kilograms | 8.44 % |
| 2008 | 3465 | Kilograms | -20.67 % |
| 2009 | 3400 | Kilograms | -1.88 % |
