Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 7445.02490234375 | Thousand metric tons | NA |
| 2010 | 8430 | Thousand metric tons | 13.23% |
| 2011 | 8812.4931640625 | Thousand metric tons | 4.54% |
| 2012 | 10798.3671875 | Thousand metric tons | 22.53% |
| 2013 | 10800 | Thousand metric tons | 0.02% |
