Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 397259 | Metric tons | NA |
| 2004 | 404776 | Metric tons | 1.89% |
| 2005 | 920000 | Metric tons | 127.29% |
| 2006 | 941000 | Metric tons | 2.28% |
| 2007 | 957000 | Metric tons | 1.70% |
| 2008 | 807000 | Metric tons | -15.67% |
| 2009 | 800000 | Metric tons | -0.87% |
