Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2005 | 75 | Thousand metric tons | NA |
| 2006 | 77.3000030517578 | Thousand metric tons | 3.07 % |
| 2007 | 89.5 | Thousand metric tons | 15.78 % |
| 2008 | 90 | Thousand metric tons | 0.56 % |
| 2009 | 90 | Thousand metric tons | 0.00 % |
