Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 152383 | Metric tons | NA |
| 2004 | 192942 | Metric tons | 26.62 % |
| 2005 | 188000 | Metric tons | -2.56 % |
| 2006 | 188000 | Metric tons | 0.00 % |
| 2007 | 188000 | Metric tons | 0.00 % |
| 2008 | 336000 | Metric tons | 78.72 % |
| 2009 | 138000 | Metric tons | -58.93 % |
