Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 105910 | Metric tons | NA |
| 2004 | 152679 | Metric tons | 44.16% |
| 2005 | 163499 | Metric tons | 7.09% |
| 2006 | 129295 | Metric tons | -20.92% |
| 2007 | 184070 | Metric tons | 42.36% |
| 2008 | 180000 | Metric tons | -2.21% |
| 2009 | 180000 | Metric tons | 0.00% |
