Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 601000 | Metric tons | NA |
| 2003 | 525000 | Metric tons | -12.65% |
| 2004 | 576000 | Metric tons | 9.71% |
| 2005 | 586000 | Metric tons | 1.74% |
| 2006 | 667000 | Metric tons | 13.82% |
| 2007 | 665000 | Metric tons | -0.30% |
| 2008 | 800000 | Metric tons | 20.30% |
| 2009 | 705000 | Metric tons | -11.88% |
| 2010 | 679000 | Metric tons | -3.69% |
| 2011 | 666000 | Metric tons | -1.91% |
| 2012 | 696000 | Metric tons | 4.50% |
