Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 573 | Thousand metric tons | NA |
| 2004 | 916.927978515625 | Thousand metric tons | 60.02% |
| 2005 | 1031.61804199219 | Thousand metric tons | 12.51% |
| 2006 | 854.046997070313 | Thousand metric tons | -17.21% |
| 2007 | 866.932983398438 | Thousand metric tons | 1.51% |
| 2008 | 1018.3330078125 | Thousand metric tons | 17.46% |
| 2009 | 850 | Thousand metric tons | -16.53% |
