Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 1853 | Metric tons | NA |
| 2003 | 1578 | Metric tons | -14.84% |
| 2004 | 1701 | Metric tons | 7.79% |
| 2005 | 1259 | Metric tons | -25.98% |
| 2006 | 2902 | Metric tons | 130.50% |
| 2007 | 4196 | Metric tons | 44.59% |
| 2008 | 1151 | Metric tons | -72.57% |
| 2009 | 1251 | Metric tons | 8.69% |
| 2010 | 861 | Metric tons | -31.18% |
| 2011 | 890 | Metric tons | 3.37% |
| 2012 | 690 | Metric tons | -22.47% |
