Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 35 | Thousand metric tons | NA |
| 2004 | 360 | Thousand metric tons | 928.57 % |
| 2005 | 450 | Thousand metric tons | 25.00 % |
| 2006 | 350 | Thousand metric tons | -22.22 % |
| 2007 | 350 | Thousand metric tons | 0.00 % |
