Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 1943 | Kilograms | NA |
| 2003 | 3449 | Kilograms | 77.51% |
| 2004 | 3564 | Kilograms | 3.33% |
| 2005 | 3879 | Kilograms | 8.84% |
| 2006 | 4022 | Kilograms | 3.69% |
| 2007 | 4180 | Kilograms | 3.93% |
| 2008 | 4386 | Kilograms | 4.93% |
| 2009 | 5680 | Kilograms | 29.50% |
