Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 1050000 | Metric tons | NA |
| 2010 | 1070000 | Metric tons | 1.90% |
| 2011 | 1210000 | Metric tons | 13.08% |
| 2012 | 1240000 | Metric tons | 2.48% |
| 2013 | 1230000 | Metric tons | -0.81% |
