Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 88142 | Metric tons | NA |
| 2003 | 71694 | Metric tons | -18.66 % |
| 2004 | 65772 | Metric tons | -8.26 % |
| 2005 | 78404 | Metric tons | 19.21 % |
| 2006 | 80933 | Metric tons | 3.23 % |
| 2007 | 66137 | Metric tons | -18.28 % |
| 2008 | 53228 | Metric tons | -19.52 % |
| 2009 | 55000 | Metric tons | 3.33 % |
