Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 286.022003173828 | Thousand metric tons | NA |
| 2004 | 270.600006103516 | Thousand metric tons | -5.39 % |
| 2005 | 272.399993896484 | Thousand metric tons | 0.67 % |
| 2006 | 319.5 | Thousand metric tons | 17.29 % |
| 2007 | 398 | Thousand metric tons | 24.57 % |
| 2008 | 787 | Thousand metric tons | 97.74 % |
| 2009 | 785 | Thousand metric tons | -0.25 % |
