Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 79.7939987182617 | Thousand metric tons | NA |
| 2004 | 72 | Thousand metric tons | -9.77% |
| 2005 | 84 | Thousand metric tons | 16.67% |
| 2006 | 85 | Thousand metric tons | 1.19% |
| 2007 | 87 | Thousand metric tons | 2.35% |
