Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 231000 | Thousand metric tons | NA |
| 2003 | 261000 | Thousand metric tons | 12.99% |
| 2004 | 320000 | Thousand metric tons | 22.61% |
| 2005 | 420000 | Thousand metric tons | 31.25% |
| 2006 | 601000 | Thousand metric tons | 43.10% |
| 2007 | 707000 | Thousand metric tons | 17.64% |
| 2008 | 824000 | Thousand metric tons | 16.55% |
| 2009 | 880000 | Thousand metric tons | 6.80% |
| 2010 | 1070000 | Thousand metric tons | 21.59% |
| 2011 | 1330000 | Thousand metric tons | 24.30% |
| 2012 | 1310000 | Thousand metric tons | -1.50% |
