Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 710000 | Metric tons | NA |
| 2004 | 700000 | Metric tons | -1.41% |
| 2005 | 720000 | Metric tons | 2.86% |
| 2006 | 720000 | Metric tons | 0.00% |
| 2007 | 800000 | Metric tons | 11.11% |
| 2008 | 810000 | Metric tons | 1.25% |
| 2009 | 450000 | Metric tons | -44.44% |
| 2010 | 700000 | Metric tons | 55.56% |
| 2011 | 800000 | Metric tons | 14.29% |
| 2012 | 820000 | Metric tons | 2.50% |
| 2013 | 750000 | Metric tons | -8.54% |
