Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 74938 | Metric tons | NA |
| 2004 | 69252 | Metric tons | -7.59% |
| 2005 | 97000 | Metric tons | 40.07% |
| 2006 | 136000 | Metric tons | 40.21% |
| 2007 | 149000 | Metric tons | 9.56% |
| 2008 | 145000 | Metric tons | -2.68% |
| 2009 | 109000 | Metric tons | -24.83% |
| 2010 | 130521 | Metric tons | 19.74% |
| 2011 | 119323 | Metric tons | -8.58% |
| 2012 | 129930 | Metric tons | 8.89% |
| 2013 | 130000 | Metric tons | 0.05% |
