Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 62000 | Metric tons | NA |
| 2003 | 102000 | Metric tons | 64.52 % |
| 2004 | 118000 | Metric tons | 15.69 % |
| 2005 | 126000 | Metric tons | 6.78 % |
| 2006 | 126000 | Metric tons | 0.00 % |
| 2007 | 146000 | Metric tons | 15.87 % |
| 2008 | 110000 | Metric tons | -24.66 % |
| 2009 | 115000 | Metric tons | 4.55 % |
