Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 895616 | Metric tons | NA |
| 2004 | 1035975 | Metric tons | 15.67% |
| 2005 | 1860037 | Metric tons | 79.54% |
| 2006 | 3515644 | Metric tons | 89.01% |
| 2007 | 3995423 | Metric tons | 13.65% |
| 2008 | 4000000 | Metric tons | 0.11% |
| 2009 | 3500000 | Metric tons | -12.50% |
