Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 300.707000732422 | Thousand metric tons | NA |
| 2004 | 473.207000732422 | Thousand metric tons | 57.36 % |
| 2005 | 461.242004394531 | Thousand metric tons | -2.53 % |
| 2006 | 446.239990234375 | Thousand metric tons | -3.25 % |
| 2007 | 456.665985107422 | Thousand metric tons | 2.34 % |
| 2008 | 472.611999511719 | Thousand metric tons | 3.49 % |
| 2009 | 450 | Thousand metric tons | -4.78 % |
