Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 531.991027832031 | Thousand metric tons | NA |
| 2004 | 531.6259765625 | Thousand metric tons | -0.07 % |
| 2005 | 750.710021972656 | Thousand metric tons | 41.21 % |
| 2006 | 872.388000488281 | Thousand metric tons | 16.21 % |
| 2007 | 865.047973632813 | Thousand metric tons | -0.84 % |
| 2008 | 871.658020019531 | Thousand metric tons | 0.76 % |
| 2009 | 870 | Thousand metric tons | -0.19 % |
