Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 480.161987304688 | Thousand metric tons | NA |
| 2004 | 553.60498046875 | Thousand metric tons | 15.30 % |
| 2005 | 461.180999755859 | Thousand metric tons | -16.69 % |
| 2006 | 1436.77600097656 | Thousand metric tons | 211.54 % |
| 2007 | 2227 | Thousand metric tons | 55.00 % |
| 2008 | 1756.708984375 | Thousand metric tons | -21.12 % |
| 2009 | 454.713989257813 | Thousand metric tons | -74.12 % |
