Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 200000 | Metric tons | NA |
| 2004 | 230000 | Metric tons | 15.00% |
| 2005 | 280000 | Metric tons | 21.74% |
| 2006 | 206000 | Metric tons | -26.43% |
| 2007 | 260000 | Metric tons | 26.21% |
| 2008 | 220000 | Metric tons | -15.38% |
| 2009 | 100000 | Metric tons | -54.55% |
