Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 187198 | Thousand metric tons | NA |
| 2003 | 212981 | Thousand metric tons | 13.77 % |
| 2004 | 233994 | Thousand metric tons | 9.87 % |
| 2005 | 262000 | Thousand metric tons | 11.97 % |
| 2006 | 275000 | Thousand metric tons | 4.96 % |
| 2007 | 299000 | Thousand metric tons | 8.73 % |
| 2008 | 342000 | Thousand metric tons | 14.38 % |
| 2009 | 394000 | Thousand metric tons | 15.20 % |
| 2010 | 433000 | Thousand metric tons | 9.90 % |
| 2011 | 488000 | Thousand metric tons | 12.70 % |
| 2012 | 521000 | Thousand metric tons | 6.76 % |
