Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 260574 | Metric tons | NA |
| 2003 | 279254 | Metric tons | 7.17% |
| 2004 | 327432 | Metric tons | 17.25% |
| 2005 | 336376 | Metric tons | 2.73% |
| 2006 | 241536 | Metric tons | -28.19% |
| 2007 | 230500 | Metric tons | -4.57% |
| 2008 | 172000 | Metric tons | -25.38% |
| 2009 | 173000 | Metric tons | 0.58% |
| 2010 | 170100 | Metric tons | -1.68% |
| 2011 | 295000 | Metric tons | 73.43% |
| 2012 | 343000 | Metric tons | 16.27% |
