Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 66630 | Thousand metric tons | NA |
| 2010 | 70380 | Thousand metric tons | 5.63% |
| 2011 | 67420 | Thousand metric tons | -4.21% |
| 2012 | 69120 | Thousand metric tons | 2.52% |
| 2013 | 70000 | Thousand metric tons | 1.27% |
