Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 142238 | Kilograms | NA |
| 2003 | 141019 | Kilograms | -0.86% |
| 2004 | 91710 | Kilograms | -34.97% |
| 2005 | 130620 | Kilograms | 42.43% |
| 2006 | 93176 | Kilograms | -28.67% |
| 2007 | 117851 | Kilograms | 26.48% |
| 2008 | 64390 | Kilograms | -45.36% |
| 2009 | 140488 | Kilograms | 118.18% |
| 2010 | 106316 | Kilograms | -24.32% |
| 2011 | 96100 | Kilograms | -9.61% |
| 2012 | 58800 | Kilograms | -38.81% |
