Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 4900000 | Metric tons | NA |
| 2004 | 6500000 | Metric tons | 32.65% |
| 2005 | 6600000 | Metric tons | 1.54% |
| 2006 | 6700000 | Metric tons | 1.52% |
| 2007 | 8000000 | Metric tons | 19.40% |
| 2008 | 10000000 | Metric tons | 25.00% |
| 2009 | 11000000 | Metric tons | 10.00% |
