Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 1561 | Thousand metric tons | NA |
| 2003 | 1541 | Thousand metric tons | -1.28 % |
| 2004 | 1546.30004882813 | Thousand metric tons | 0.34 % |
| 2005 | 1550 | Thousand metric tons | 0.24 % |
| 2006 | 1470 | Thousand metric tons | -5.16 % |
| 2007 | 1728 | Thousand metric tons | 17.55 % |
| 2008 | 3000 | Thousand metric tons | 73.61 % |
