Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 148 | Thousand metric tons | NA |
| 2003 | 162 | Thousand metric tons | 9.46 % |
| 2004 | 61.9000015258789 | Thousand metric tons | -61.79 % |
| 2005 | 111.900001525879 | Thousand metric tons | 80.78 % |
| 2006 | 140.800003051758 | Thousand metric tons | 25.83 % |
| 2007 | 180 | Thousand metric tons | 27.84 % |
| 2008 | 180 | Thousand metric tons | 0.00 % |
