Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1152.69995117188 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1120 | Thousand metric tons of contained nitrogen | -2.84% |
| 2005 | 1206 | Thousand metric tons of contained nitrogen | 7.68% |
| 2006 | 616 | Thousand metric tons of contained nitrogen | -48.92% |
| 2007 | 800 | Thousand metric tons of contained nitrogen | 29.87% |
| 2008 | 800 | Thousand metric tons of contained nitrogen | 0.00% |
| 2009 | 2970 | Thousand metric tons of contained nitrogen | 271.25% |
| 2010 | 3517 | Thousand metric tons of contained nitrogen | 18.42% |
| 2011 | 3500 | Thousand metric tons of contained nitrogen | -0.48% |
| 2012 | 2644 | Thousand metric tons of contained nitrogen | -24.46% |
