Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 146845 | Metric tons | NA |
| 2004 | 163028 | Metric tons | 11.02% |
| 2005 | 247101 | Metric tons | 51.57% |
| 2006 | 246165 | Metric tons | -0.38% |
| 2007 | 250260 | Metric tons | 1.66% |
| 2008 | 256182 | Metric tons | 2.37% |
| 2009 | 148099 | Metric tons | -42.19% |
| 2010 | 229301 | Metric tons | 54.83% |
| 2011 | 228357 | Metric tons | -0.41% |
| 2012 | 193795 | Metric tons | -15.14% |
| 2013 | 200000 | Metric tons | 3.20% |
