Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 3493 | Kilograms | NA |
| 2003 | 3096 | Kilograms | -11.37% |
| 2004 | 4064 | Kilograms | 31.27% |
| 2005 | 3674 | Kilograms | -9.60% |
| 2006 | 3595 | Kilograms | -2.15% |
| 2007 | 3400 | Kilograms | -5.42% |
| 2008 | 2965 | Kilograms | -12.79% |
| 2009 | 2590 | Kilograms | -12.65% |
| 2010 | 4900 | Kilograms | 89.19% |
| 2011 | 6395 | Kilograms | 30.51% |
| 2012 | 6980 | Kilograms | 9.15% |
