Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 544 | Thousand metric tons | NA |
| 2004 | 689 | Thousand metric tons | 26.65% |
| 2005 | 890 | Thousand metric tons | 29.17% |
| 2006 | 1400 | Thousand metric tons | 57.30% |
| 2007 | 2000 | Thousand metric tons | 42.86% |
