Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 61.5999984741211 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 136.100006103516 | Thousand metric tons of contained nitrogen | 120.94% |
| 2005 | 111 | Thousand metric tons of contained nitrogen | -18.44% |
| 2006 | 80 | Thousand metric tons of contained nitrogen | -27.93% |
| 2007 | 85 | Thousand metric tons of contained nitrogen | 6.25% |
| 2008 | 47 | Thousand metric tons of contained nitrogen | -44.71% |
| 2009 | 53 | Thousand metric tons of contained nitrogen | 12.77% |
| 2010 | 84 | Thousand metric tons of contained nitrogen | 58.49% |
| 2011 | 132 | Thousand metric tons of contained nitrogen | 57.14% |
| 2012 | 130 | Thousand metric tons of contained nitrogen | -1.52% |
