Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1007 | Thousand metric tons | NA |
| 2004 | 1026 | Thousand metric tons | 1.89% |
| 2005 | 1260 | Thousand metric tons | 22.81% |
| 2006 | 1151 | Thousand metric tons | -8.65% |
| 2007 | 1250 | Thousand metric tons | 8.60% |
