Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 767000 | Metric tons | NA |
| 2004 | 715000 | Metric tons | -6.78% |
| 2005 | 693754 | Metric tons | -2.97% |
| 2006 | 769188 | Metric tons | 10.87% |
| 2007 | 811556 | Metric tons | 5.51% |
| 2008 | 837476 | Metric tons | 3.19% |
| 2009 | 800000 | Metric tons | -4.47% |
