Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 4 | Thousand metric tons | NA |
| 2003 | 4 | Thousand metric tons | 0.00 % |
| 2004 | 8.83699989318848 | Thousand metric tons | 120.93 % |
| 2005 | 28.242000579834 | Thousand metric tons | 219.59 % |
| 2006 | 35.0340003967285 | Thousand metric tons | 24.05 % |
| 2007 | 22.0370006561279 | Thousand metric tons | -37.10 % |
| 2008 | 23 | Thousand metric tons | 4.37 % |
