Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 50000 | Metric tons | NA |
| 2004 | 50000 | Metric tons | 0.00% |
| 2005 | 50000 | Metric tons | 0.00% |
| 2006 | 60000 | Metric tons | 20.00% |
| 2007 | 80910 | Metric tons | 34.85% |
| 2008 | 103476 | Metric tons | 27.89% |
| 2009 | 113064 | Metric tons | 9.27% |
