Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 91 | Thousand metric tons | NA |
| 2004 | 107 | Thousand metric tons | 17.58% |
| 2005 | 101 | Thousand metric tons | -5.61% |
| 2006 | 115 | Thousand metric tons | 13.86% |
| 2007 | 105 | Thousand metric tons | -8.70% |
