Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 16591 | Metric tons | NA |
| 2004 | 24299 | Metric tons | 46.46% |
| 2005 | 34386 | Metric tons | 41.51% |
| 2006 | 32523 | Metric tons | -5.42% |
| 2007 | 106567 | Metric tons | 227.67% |
