Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 27200 | Metric tons | NA |
| 2004 | 57900 | Metric tons | 112.87% |
| 2005 | 55300 | Metric tons | -4.49% |
| 2006 | 62500 | Metric tons | 13.02% |
| 2007 | 65000 | Metric tons | 4.00% |
| 2008 | 65000 | Metric tons | 0.00% |
| 2009 | 65000 | Metric tons | 0.00% |
