Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 157530 | Kilograms | NA |
| 2003 | 172619 | Kilograms | 9.58 % |
| 2004 | 173224 | Kilograms | 0.35 % |
| 2005 | 208002 | Kilograms | 20.08 % |
| 2006 | 202826 | Kilograms | -2.49 % |
| 2007 | 170236 | Kilograms | -16.07 % |
| 2008 | 179872 | Kilograms | 5.66 % |
| 2009 | 182391 | Kilograms | 1.40 % |
