Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 490000 | Metric tons | NA |
| 2003 | 485000 | Metric tons | -1.02% |
| 2004 | 462100 | Metric tons | -4.72% |
| 2005 | 422000 | Metric tons | -8.68% |
| 2006 | 457000 | Metric tons | 8.29% |
| 2007 | 405000 | Metric tons | -11.38% |
| 2008 | 465000 | Metric tons | 14.81% |
| 2009 | 455000 | Metric tons | -2.15% |
| 2010 | 427000 | Metric tons | -6.15% |
| 2011 | 417000 | Metric tons | -2.34% |
| 2012 | 424000 | Metric tons | 1.68% |
