Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 294 | Metric tons | NA |
| 2003 | 285 | Metric tons | -3.06 % |
| 2004 | 262 | Metric tons | -8.07 % |
| 2005 | 320.589996337891 | Metric tons | 22.36 % |
| 2006 | 261.399993896484 | Metric tons | -18.46 % |
| 2007 | 269 | Metric tons | 2.91 % |
| 2008 | 226 | Metric tons | -15.99 % |
| 2009 | 215 | Metric tons | -4.87 % |
