Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 86.1169967651367 | Thousand metric tons | NA |
| 2004 | 98.0260009765625 | Thousand metric tons | 13.83% |
| 2005 | 87 | Thousand metric tons | -11.25% |
| 2006 | 100 | Thousand metric tons | 14.94% |
| 2007 | 100 | Thousand metric tons | 0.00% |
