Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 6800 | Thousand metric tons | NA |
| 2004 | 6800 | Thousand metric tons | 0.00 % |
| 2005 | 1609.72094726563 | Thousand metric tons | -76.33 % |
| 2006 | 2007.70300292969 | Thousand metric tons | 24.72 % |
| 2007 | 1890.02905273438 | Thousand metric tons | -5.86 % |
| 2008 | 2150.22094726563 | Thousand metric tons | 13.77 % |
| 2009 | 1500 | Thousand metric tons | -30.24 % |
