Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 462000 | Metric tons | NA |
| 2004 | 441000 | Metric tons | -4.55 % |
| 2005 | 427000 | Metric tons | -3.17 % |
| 2006 | 492000 | Metric tons | 15.22 % |
| 2007 | 601000 | Metric tons | 22.15 % |
| 2008 | 550000 | Metric tons | -8.49 % |
| 2009 | 476000 | Metric tons | -13.45 % |
