Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 90000 | Metric tons | NA |
| 2004 | 90000 | Metric tons | 0.00 % |
| 2005 | 70000 | Metric tons | -22.22 % |
| 2006 | 72000 | Metric tons | 2.86 % |
| 2007 | 79000 | Metric tons | 9.72 % |
| 2008 | 70000 | Metric tons | -11.39 % |
| 2009 | 44000 | Metric tons | -37.14 % |
