Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 2802.89990234375 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 2740.71801757813 | Thousand metric tons of contained nitrogen | -2.22% |
| 2005 | 2788.7880859375 | Thousand metric tons of contained nitrogen | 1.75% |
| 2006 | 2717.51611328125 | Thousand metric tons of contained nitrogen | -2.56% |
| 2007 | 2746.17700195313 | Thousand metric tons of contained nitrogen | 1.05% |
| 2008 | 2819.25903320313 | Thousand metric tons of contained nitrogen | 2.66% |
| 2009 | 2362.55004882813 | Thousand metric tons of contained nitrogen | -16.20% |
| 2010 | 2677.30908203125 | Thousand metric tons of contained nitrogen | 13.32% |
| 2011 | 2820.669921875 | Thousand metric tons of contained nitrogen | 5.35% |
| 2012 | 2823.40991210938 | Thousand metric tons of contained nitrogen | 0.10% |
