Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 790700 | Metric tons | NA |
| 2003 | 772600 | Metric tons | -2.29% |
| 2004 | 795800 | Metric tons | 3.00% |
| 2005 | 865300 | Metric tons | 8.73% |
| 2006 | 806400 | Metric tons | -6.81% |
| 2007 | 828000 | Metric tons | 2.68% |
| 2008 | 833000 | Metric tons | 0.60% |
| 2009 | 831000 | Metric tons | -0.24% |
| 2010 | 856000 | Metric tons | 3.01% |
| 2011 | 922300 | Metric tons | 7.75% |
| 2012 | 914000 | Metric tons | -0.90% |
