Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 70000 | Metric tons | NA |
| 2004 | 60000 | Metric tons | -14.29% |
| 2005 | 18000 | Metric tons | -70.00% |
| 2006 | 6300 | Metric tons | -65.00% |
| 2007 | 4200 | Metric tons | -33.33% |
| 2008 | 1600 | Metric tons | -61.90% |
