Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2005 | 700 | Thousand metric tons | NA |
| 2006 | 800 | Thousand metric tons | 14.29 % |
| 2007 | 1300 | Thousand metric tons | 62.50 % |
| 2008 | 900 | Thousand metric tons | -30.77 % |
| 2009 | 800 | Thousand metric tons | -11.11 % |
