Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 41662 | Kilograms | NA |
| 2003 | 40416 | Kilograms | -2.99% |
| 2004 | 47596 | Kilograms | 17.77% |
| 2005 | 38293 | Kilograms | -19.55% |
| 2006 | 43082 | Kilograms | 12.51% |
| 2007 | 50000 | Kilograms | 16.06% |
| 2008 | 54666 | Kilograms | 9.33% |
| 2009 | 60330 | Kilograms | 10.36% |
| 2010 | 62047 | Kilograms | 2.85% |
| 2011 | 65209 | Kilograms | 5.10% |
| 2012 | 65000 | Kilograms | -0.32% |
