Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1054 | Thousand metric tons | NA |
| 2004 | 1089 | Thousand metric tons | 3.32% |
| 2005 | 1057 | Thousand metric tons | -2.94% |
| 2006 | 1003 | Thousand metric tons | -5.11% |
| 2007 | 1147 | Thousand metric tons | 14.36% |
