Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 3770000 | Metric tons | NA |
| 2004 | 4550000 | Metric tons | 20.69% |
| 2005 | 4710000 | Metric tons | 3.52% |
| 2006 | 4940000 | Metric tons | 4.88% |
| 2007 | 4820000 | Metric tons | -2.43% |
| 2008 | 4910000 | Metric tons | 1.87% |
| 2009 | 3650000 | Metric tons | -25.66% |
| 2010 | 4600000 | Metric tons | 26.03% |
| 2011 | 4990000 | Metric tons | 8.48% |
| 2012 | 4980000 | Metric tons | -0.20% |
| 2013 | 4350000 | Metric tons | -12.65% |
