Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 59530 | Metric tons | NA |
| 2004 | 65100 | Metric tons | 9.36% |
| 2005 | 65000 | Metric tons | -0.15% |
| 2006 | 71000 | Metric tons | 9.23% |
| 2007 | 67000 | Metric tons | -5.63% |
| 2008 | 67000 | Metric tons | 0.00% |
| 2009 | 83000 | Metric tons | 23.88% |
| 2010 | 71000 | Metric tons | -14.46% |
| 2011 | 70899 | Metric tons | -0.14% |
| 2012 | 72364 | Metric tons | 2.07% |
| 2013 | 64000 | Metric tons | -11.56% |
