Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 130329 | Metric tons | NA |
| 2004 | 87609 | Metric tons | -32.78 % |
| 2005 | 110833 | Metric tons | 26.51 % |
| 2006 | 125000 | Metric tons | 12.78 % |
| 2007 | 125000 | Metric tons | 0.00 % |
| 2008 | 96902 | Metric tons | -22.48 % |
| 2009 | 37601 | Metric tons | -61.20 % |
