Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 173400 | Metric tons | NA |
| 2004 | 280950 | Metric tons | 62.02% |
| 2005 | 245080 | Metric tons | -12.77% |
| 2006 | 303659 | Metric tons | 23.90% |
| 2007 | 354903 | Metric tons | 16.88% |
| 2008 | 174729 | Metric tons | -50.77% |
| 2009 | 200000 | Metric tons | 14.46% |
