Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 21.3999996185303 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 51.2999992370605 | Thousand metric tons of contained nitrogen | 139.72% |
| 2005 | 27.8999996185303 | Thousand metric tons of contained nitrogen | -45.61% |
| 2006 | 42.2999992370605 | Thousand metric tons of contained nitrogen | 51.61% |
| 2007 | 47.4000015258789 | Thousand metric tons of contained nitrogen | 12.06% |
| 2008 | 41.7000007629395 | Thousand metric tons of contained nitrogen | -12.03% |
| 2009 | 27.2000007629395 | Thousand metric tons of contained nitrogen | -34.77% |
| 2010 | 36 | Thousand metric tons of contained nitrogen | 32.35% |
| 2011 | 45.2000007629395 | Thousand metric tons of contained nitrogen | 25.56% |
| 2012 | 59 | Thousand metric tons of contained nitrogen | 30.53% |
