Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 63758 | Kilograms | NA |
| 2003 | 70946 | Kilograms | 11.27% |
| 2004 | 76403 | Kilograms | 7.69% |
| 2005 | 82961 | Kilograms | 8.58% |
| 2006 | 86265 | Kilograms | 3.98% |
| 2007 | 83643 | Kilograms | -3.04% |
| 2008 | 75537 | Kilograms | -9.69% |
| 2009 | 75118 | Kilograms | -0.55% |
