Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 23101 | Metric tons | NA |
| 2004 | 39797 | Metric tons | 72.27 % |
| 2005 | 42791 | Metric tons | 7.52 % |
| 2006 | 45000 | Metric tons | 5.16 % |
| 2007 | 62015 | Metric tons | 37.81 % |
| 2008 | 56077 | Metric tons | -9.58 % |
| 2009 | 60000 | Metric tons | 7.00 % |
