Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 58976 | Metric tons | NA |
| 2004 | 121452 | Metric tons | 105.93% |
| 2005 | 122887 | Metric tons | 1.18% |
| 2006 | 77285 | Metric tons | -37.11% |
| 2007 | 171589 | Metric tons | 122.02% |
| 2008 | 172000 | Metric tons | 0.24% |
