Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 750 | Thousand metric tons | NA |
| 2004 | 850 | Thousand metric tons | 13.33% |
| 2005 | 889 | Thousand metric tons | 4.59% |
| 2006 | 862 | Thousand metric tons | -3.04% |
| 2007 | 845 | Thousand metric tons | -1.97% |
