Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 20016 | Metric tons | NA |
| 2004 | 27150 | Metric tons | 35.64% |
| 2005 | 23045 | Metric tons | -15.12% |
| 2006 | 20000 | Metric tons | -13.21% |
| 2007 | 15000 | Metric tons | -25.00% |
| 2008 | 15000 | Metric tons | 0.00% |
| 2009 | 3211 | Metric tons | -78.59% |
