Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 81100 | Metric tons | NA |
| 2003 | 78600 | Metric tons | -3.08 % |
| 2004 | 99200 | Metric tons | 26.21 % |
| 2005 | 78100 | Metric tons | -21.27 % |
| 2006 | 110000 | Metric tons | 40.85 % |
| 2007 | 96600 | Metric tons | -12.18 % |
| 2008 | 84000 | Metric tons | -13.04 % |
| 2009 | 50100 | Metric tons | -40.36 % |
