Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 32506 | Kilograms | NA |
| 2003 | 29749 | Kilograms | -8.48 % |
| 2004 | 28466 | Kilograms | -4.31 % |
| 2005 | 27904 | Kilograms | -1.97 % |
| 2006 | 44131 | Kilograms | 58.15 % |
| 2007 | 42021 | Kilograms | -4.78 % |
| 2008 | 42046 | Kilograms | 0.06 % |
| 2009 | 47000 | Kilograms | 11.78 % |
