Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 4984 | Kilograms | NA |
| 2003 | 5000 | Kilograms | 0.32% |
| 2004 | 5000 | Kilograms | 0.00% |
| 2005 | 4438 | Kilograms | -11.24% |
| 2006 | 4100 | Kilograms | -7.62% |
| 2007 | 3275 | Kilograms | -20.12% |
| 2008 | 2561 | Kilograms | -21.80% |
| 2009 | 2127 | Kilograms | -16.95% |
| 2010 | 2197 | Kilograms | 3.29% |
| 2011 | 1893 | Kilograms | -13.84% |
| 2012 | 1858 | Kilograms | -1.85% |
