Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 744 | Thousand metric tons | NA |
| 2003 | 766 | Thousand metric tons | 2.96 % |
| 2004 | 768.400024414063 | Thousand metric tons | 0.31 % |
| 2005 | 686.400024414063 | Thousand metric tons | -10.67 % |
| 2006 | 883 | Thousand metric tons | 28.64 % |
| 2007 | 890 | Thousand metric tons | 0.79 % |
| 2008 | 800 | Thousand metric tons | -10.11 % |
