Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 886 | Thousand metric tons | NA |
| 2004 | 1012.59997558594 | Thousand metric tons | 14.29% |
| 2005 | 1016 | Thousand metric tons | 0.34% |
| 2006 | 675.400024414063 | Thousand metric tons | -33.52% |
| 2007 | 995 | Thousand metric tons | 47.32% |
