Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1061.20397949219 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1101.42602539063 | Thousand metric tons of contained nitrogen | 3.79% |
| 2005 | 1083.15002441406 | Thousand metric tons of contained nitrogen | -1.66% |
| 2006 | 1091 | Thousand metric tons of contained nitrogen | 0.72% |
| 2007 | 1114 | Thousand metric tons of contained nitrogen | 2.11% |
| 2008 | 1244 | Thousand metric tons of contained nitrogen | 11.67% |
| 2009 | 1021 | Thousand metric tons of contained nitrogen | -17.93% |
| 2010 | 1178 | Thousand metric tons of contained nitrogen | 15.38% |
| 2011 | 1211 | Thousand metric tons of contained nitrogen | 2.80% |
| 2012 | 1055 | Thousand metric tons of contained nitrogen | -12.88% |
