Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 48253 | Metric tons | NA |
| 2003 | 58000 | Metric tons | 20.20% |
| 2004 | 49000 | Metric tons | -15.52% |
| 2005 | 54000 | Metric tons | 10.20% |
| 2006 | 46000 | Metric tons | -14.81% |
| 2007 | 81000 | Metric tons | 76.09% |
| 2008 | 100000 | Metric tons | 23.46% |
| 2009 | 105000 | Metric tons | 5.00% |
| 2010 | 97000 | Metric tons | -7.62% |
| 2011 | 80000 | Metric tons | -17.53% |
| 2012 | 90000 | Metric tons | 12.50% |
