Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1789.5 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1675.19995117188 | Thousand metric tons of contained nitrogen | -6.39% |
| 2005 | 1640 | Thousand metric tons of contained nitrogen | -2.10% |
| 2006 | 1800 | Thousand metric tons of contained nitrogen | 9.76% |
| 2007 | 1750 | Thousand metric tons of contained nitrogen | -2.78% |
| 2008 | 2500 | Thousand metric tons of contained nitrogen | 42.86% |
| 2009 | 1790 | Thousand metric tons of contained nitrogen | -28.40% |
| 2010 | 3000 | Thousand metric tons of contained nitrogen | 67.60% |
| 2011 | 3500 | Thousand metric tons of contained nitrogen | 16.67% |
| 2012 | 2950 | Thousand metric tons of contained nitrogen | -15.71% |
