Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 48253 | Metric tons | NA |
| 2003 | 58000 | Metric tons | 20.20 % |
| 2004 | 49000 | Metric tons | -15.52 % |
| 2005 | 54000 | Metric tons | 10.20 % |
| 2006 | 46000 | Metric tons | -14.81 % |
| 2007 | 81000 | Metric tons | 76.09 % |
| 2008 | 83000 | Metric tons | 2.47 % |
