Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 42662 | Metric tons | NA |
| 2004 | 79220 | Metric tons | 85.69% |
| 2005 | 117180 | Metric tons | 47.92% |
| 2006 | 142358 | Metric tons | 21.49% |
| 2007 | 358775 | Metric tons | 152.02% |
| 2008 | 300000 | Metric tons | -16.38% |
