Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 136633 | Metric tons | NA |
| 2004 | 133829 | Metric tons | -2.05 % |
| 2005 | 156935 | Metric tons | 17.27 % |
| 2006 | 260000 | Metric tons | 65.67 % |
| 2007 | 270000 | Metric tons | 3.85 % |
| 2008 | 270000 | Metric tons | 0.00 % |
| 2009 | 230000 | Metric tons | -14.81 % |
