Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 126116 | Metric tons | NA |
| 2004 | 98262 | Metric tons | -22.09% |
| 2005 | 133344 | Metric tons | 35.70% |
| 2006 | 257570 | Metric tons | 93.16% |
| 2007 | 371952 | Metric tons | 44.41% |
| 2008 | 372000 | Metric tons | 0.01% |
