Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 26495 | Metric tons | NA |
| 2004 | 31259 | Metric tons | 17.98% |
| 2005 | 31000 | Metric tons | -0.83% |
| 2006 | 40000 | Metric tons | 29.03% |
| 2007 | 30000 | Metric tons | -25.00% |
| 2008 | 30000 | Metric tons | 0.00% |
| 2009 | 30000 | Metric tons | 0.00% |
