Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 86400 | Thousand metric tons | NA |
| 2003 | 99100 | Thousand metric tons | 14.70% |
| 2004 | 120600 | Thousand metric tons | 21.70% |
| 2005 | 152000 | Thousand metric tons | 26.04% |
| 2006 | 181000 | Thousand metric tons | 19.08% |
| 2007 | 202000 | Thousand metric tons | 11.60% |
| 2008 | 213033 | Thousand metric tons | 5.46% |
| 2009 | 217155 | Thousand metric tons | 1.93% |
| 2010 | 210006 | Thousand metric tons | -3.29% |
| 2011 | 177256 | Thousand metric tons | -15.59% |
| 2012 | 143710 | Thousand metric tons | -18.93% |
