Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 199000 | Metric tons | NA |
| 2004 | 201000 | Metric tons | 1.01% |
| 2005 | 216000 | Metric tons | 7.46% |
| 2006 | 267000 | Metric tons | 23.61% |
| 2007 | 335000 | Metric tons | 25.47% |
| 2008 | 174000 | Metric tons | -48.06% |
| 2009 | 177000 | Metric tons | 1.72% |
| 2010 | 183000 | Metric tons | 3.39% |
| 2011 | 160000 | Metric tons | -12.57% |
| 2012 | 221000 | Metric tons | 38.13% |
| 2013 | 226000 | Metric tons | 2.26% |
