Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 679 | Thousand metric tons | NA |
| 2010 | 975 | Thousand metric tons | 43.59% |
| 2011 | 862 | Thousand metric tons | -11.59% |
| 2012 | 1178 | Thousand metric tons | 36.66% |
| 2013 | 1200 | Thousand metric tons | 1.87% |
