Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 433.799987792969 | Thousand metric tons | NA |
| 2004 | 80 | Thousand metric tons | -81.56% |
| 2005 | 73.6399993896484 | Thousand metric tons | -7.95% |
| 2006 | 80.515998840332 | Thousand metric tons | 9.34% |
| 2007 | 75 | Thousand metric tons | -6.85% |
