Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 169034 | Metric tons | NA |
| 2004 | 191312 | Metric tons | 13.18% |
| 2005 | 159207 | Metric tons | -16.78% |
| 2006 | 199755 | Metric tons | 25.47% |
| 2007 | 210373 | Metric tons | 5.32% |
