Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 578.200012207031 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 542.799987792969 | Thousand metric tons of contained nitrogen | -6.12% |
| 2005 | 550 | Thousand metric tons of contained nitrogen | 1.33% |
| 2006 | 470 | Thousand metric tons of contained nitrogen | -14.55% |
| 2007 | 524 | Thousand metric tons of contained nitrogen | 11.49% |
| 2008 | 500 | Thousand metric tons of contained nitrogen | -4.58% |
| 2009 | 500 | Thousand metric tons of contained nitrogen | 0.00% |
| 2010 | 600 | Thousand metric tons of contained nitrogen | 20.00% |
| 2011 | 593 | Thousand metric tons of contained nitrogen | -1.17% |
| 2012 | 713 | Thousand metric tons of contained nitrogen | 20.24% |
