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 | 359 | Metric tons | 58.85% |
| 2010 | 272 | Metric tons | -24.23% |
| 2011 | 310 | Metric tons | 13.97% |
| 2012 | 250 | Metric tons | -19.35% |
