Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 115000 | Thousand metric tons | NA |
| 2003 | 123000 | Thousand metric tons | 6.96% |
| 2004 | 130000 | Thousand metric tons | 5.69% |
| 2005 | 145000 | Thousand metric tons | 11.54% |
| 2006 | 160000 | Thousand metric tons | 10.34% |
| 2007 | 170000 | Thousand metric tons | 6.25% |
| 2008 | 185000 | Thousand metric tons | 8.82% |
| 2009 | 205000 | Thousand metric tons | 10.81% |
| 2010 | 220000 | Thousand metric tons | 7.32% |
| 2011 | 250000 | Thousand metric tons | 13.64% |
| 2012 | 270000 | Thousand metric tons | 8.00% |
