Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 3800 | Kilograms | NA |
| 2003 | 3200 | Kilograms | -15.79% |
| 2004 | 3700 | Kilograms | 15.63% |
| 2005 | 3100 | Kilograms | -16.22% |
| 2006 | 2400 | Kilograms | -22.58% |
| 2007 | 3000 | Kilograms | 25.00% |
| 2008 | 2700 | Kilograms | -10.00% |
| 2009 | 2800 | Kilograms | 3.70% |
| 2010 | 2700 | Kilograms | -3.57% |
| 2011 | 2300 | Kilograms | -14.81% |
| 2012 | 1800 | Kilograms | -21.74% |
