Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 140528 | Metric tons | NA |
| 2004 | 193046 | Metric tons | 37.37 % |
| 2005 | 261888 | Metric tons | 35.66 % |
| 2006 | 260000 | Metric tons | -0.72 % |
| 2007 | 254084 | Metric tons | -2.28 % |
| 2008 | 240000 | Metric tons | -5.54 % |
| 2009 | 250000 | Metric tons | 4.17 % |
