Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 8615 | Kilograms | NA |
| 2003 | 8143 | Kilograms | -5.48 % |
| 2004 | 8021 | Kilograms | -1.50 % |
| 2005 | 8318 | Kilograms | 3.70 % |
| 2006 | 8904 | Kilograms | 7.04 % |
| 2007 | 8869 | Kilograms | -0.39 % |
| 2008 | 6868 | Kilograms | -22.56 % |
| 2009 | 7000 | Kilograms | 1.92 % |
