Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 5459 | Metric tons | NA |
| 2004 | 6231 | Metric tons | 14.14 % |
| 2005 | 5362 | Metric tons | -13.95 % |
| 2006 | 5517 | Metric tons | 2.89 % |
| 2007 | 12367 | Metric tons | 124.16 % |
| 2008 | 8447 | Metric tons | -31.70 % |
| 2009 | 8500 | Metric tons | 0.63 % |
