Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 738 | Thousand metric tons | NA |
| 2004 | 887 | Thousand metric tons | 20.19% |
| 2005 | 740 | Thousand metric tons | -16.57% |
| 2006 | 573 | Thousand metric tons | -22.57% |
| 2007 | 610 | Thousand metric tons | 6.46% |
