Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 40000 | Metric tons | NA |
| 2004 | 54145 | Metric tons | 35.36% |
| 2005 | 38780 | Metric tons | -28.38% |
| 2006 | 40000 | Metric tons | 3.15% |
| 2007 | 41000 | Metric tons | 2.50% |
| 2008 | 44000 | Metric tons | 7.32% |
| 2009 | 44000 | Metric tons | 0.00% |
| 2010 | 12934 | Metric tons | -70.60% |
| 2011 | 48000 | Metric tons | 271.11% |
| 2012 | 45000 | Metric tons | -6.25% |
| 2013 | 50000 | Metric tons | 11.11% |
