Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 10414 | Thousand metric tons | NA |
| 2004 | 11285 | Thousand metric tons | 8.36% |
| 2005 | 12385 | Thousand metric tons | 9.75% |
| 2006 | 13940 | Thousand metric tons | 12.56% |
| 2007 | 20343 | Thousand metric tons | 45.93% |
| 2008 | 21210 | Thousand metric tons | 4.26% |
| 2009 | 16000 | Thousand metric tons | -24.56% |
