Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 137596 | Metric tons | NA |
| 2004 | 138000 | Metric tons | 0.29 % |
| 2005 | 166569 | Metric tons | 20.70 % |
| 2006 | 159447 | Metric tons | -4.28 % |
| 2007 | 153409 | Metric tons | -3.79 % |
| 2008 | 154577 | Metric tons | 0.76 % |
| 2009 | 150000 | Metric tons | -2.96 % |
