Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 439.100006103516 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 559.900024414063 | Thousand metric tons of contained nitrogen | 27.51% |
| 2005 | 422.600006103516 | Thousand metric tons of contained nitrogen | -24.52% |
| 2006 | 486.623992919922 | Thousand metric tons of contained nitrogen | 15.15% |
| 2007 | 486.700012207031 | Thousand metric tons of contained nitrogen | 0.02% |
| 2008 | 736.512023925781 | Thousand metric tons of contained nitrogen | 51.33% |
| 2009 | 861.033996582031 | Thousand metric tons of contained nitrogen | 16.91% |
| 2010 | 824.372985839844 | Thousand metric tons of contained nitrogen | -4.26% |
| 2011 | 765.5 | Thousand metric tons of contained nitrogen | -7.14% |
| 2012 | 879.700012207031 | Thousand metric tons of contained nitrogen | 14.92% |
