Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 75000 | Metric tons | NA |
| 2004 | 80000 | Metric tons | 6.67 % |
| 2005 | 104500 | Metric tons | 30.63 % |
| 2006 | 124000 | Metric tons | 18.66 % |
| 2007 | 137000 | Metric tons | 10.48 % |
| 2008 | 135000 | Metric tons | -1.46 % |
| 2009 | 140000 | Metric tons | 3.70 % |
