Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 119648 | Metric tons | NA |
| 2004 | 134504 | Metric tons | 12.42% |
| 2005 | 157179 | Metric tons | 16.86% |
| 2006 | 161993 | Metric tons | 3.06% |
| 2007 | 184041 | Metric tons | 13.61% |
| 2008 | 482740 | Metric tons | 162.30% |
| 2009 | 213187 | Metric tons | -55.84% |
| 2010 | 172618 | Metric tons | -19.03% |
| 2011 | 250786 | Metric tons | 45.28% |
| 2012 | 260000 | Metric tons | 3.67% |
