Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 69271 | Kilograms | NA |
| 2003 | 70749 | Kilograms | 2.13 % |
| 2004 | 63139 | Kilograms | -10.76 % |
| 2005 | 66852 | Kilograms | 5.88 % |
| 2006 | 69817 | Kilograms | 4.44 % |
| 2007 | 83558 | Kilograms | 19.68 % |
| 2008 | 80503 | Kilograms | -3.66 % |
| 2009 | 86000 | Kilograms | 6.83 % |
