Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 13581 | Kilograms | NA |
| 2003 | 11707 | Kilograms | -13.80% |
| 2004 | 11148 | Kilograms | -4.77% |
| 2005 | 8325 | Kilograms | -25.32% |
| 2006 | 5668 | Kilograms | -31.92% |
| 2007 | 7412 | Kilograms | 30.77% |
| 2008 | 8131 | Kilograms | 9.70% |
| 2009 | 9326 | Kilograms | 14.70% |
| 2010 | 9594 | Kilograms | 2.87% |
| 2011 | 11293 | Kilograms | 17.71% |
| 2012 | 13643 | Kilograms | 20.81% |
