Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 4666 | Kilograms | NA |
| 2003 | 5409 | Kilograms | 15.92% |
| 2004 | 5004 | Kilograms | -7.49% |
| 2005 | 5000 | Kilograms | -0.08% |
| 2006 | 5000 | Kilograms | 0.00% |
| 2007 | 5000 | Kilograms | 0.00% |
| 2008 | 4148 | Kilograms | -17.04% |
| 2009 | 5749 | Kilograms | 38.60% |
| 2010 | 7628 | Kilograms | 32.68% |
| 2011 | 8461 | Kilograms | 10.92% |
| 2012 | 10814 | Kilograms | 27.81% |
