Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 30000 | Metric tons | NA |
| 2004 | 32110 | Metric tons | 7.03% |
| 2005 | 11850 | Metric tons | -63.10% |
| 2006 | 15176 | Metric tons | 28.07% |
| 2007 | 14837 | Metric tons | -2.23% |
| 2008 | 15000 | Metric tons | 1.10% |
