Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 176000 | Metric tons | NA |
| 2004 | 202000 | Metric tons | 14.77% |
| 2005 | 207048 | Metric tons | 2.50% |
| 2006 | 179493 | Metric tons | -13.31% |
| 2007 | 159395 | Metric tons | -11.20% |
| 2008 | 164042 | Metric tons | 2.92% |
| 2009 | 127689 | Metric tons | -22.16% |
| 2009 | 128000 | Metric tons | 0.24% |
| 2010 | 184696 | Metric tons | 44.29% |
| 2011 | 202313 | Metric tons | 9.54% |
| 2012 | 173940 | Metric tons | -14.02% |
| 2013 | 172000 | Metric tons | -1.12% |
