Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 3224278 | Metric tons | NA |
| 2004 | 3732952 | Metric tons | 15.78% |
| 2005 | 2372206 | Metric tons | -36.45% |
| 2006 | 2088033 | Metric tons | -11.98% |
| 2007 | 1984908 | Metric tons | -4.94% |
| 2008 | 2143047 | Metric tons | 7.97% |
| 2009 | 2000000 | Metric tons | -6.67% |
