Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 0.899999976158142 | Thousand metric tons | NA |
| 2003 | 0.699999988079071 | Thousand metric tons | -22.22 % |
| 2004 | 0.5 | Thousand metric tons | -28.57 % |
