| Year | BOD5 1992-2012 (539) | BOD5 2000-2012 (1235) | Ammonium 1992-2012 (799) | Ammonium 2000-2012 (1336) | Rivers nitrate 1992-2012 (1059) | Rivers nitrate 2000-2012 (1653) | Rivers phosphate 1992-2012 (874) | Rivers phosphate 2000-2012 (1470) |
|---|---|---|---|---|---|---|---|---|
| 1992 | 3.62 | 411 | 2.66 | 0.133 | ||||
| 1993 | 3.7 | 419 | 2.57 | 0.134 | ||||
| 1994 | 3.26 | 346 | 2.51 | 0.115 | ||||
| 1995 | 3.06 | 305 | 2.45 | 0.119 | ||||
| 1996 | 3.14 | 357 | 2.56 | 0.129 | ||||
| 1997 | 3.01 | 301 | 2.49 | 0.12 | ||||
| 1998 | 2.84 | 247 | 2.59 | 0.107 | ||||
| 1999 | 2.75 | 200 | 2.41 | 0.099 | ||||
| 2000 | 2.76 | 2.95 | 197 | 307 | 2.39 | 2.08 | 0.094 | 0.106 |
| 2001 | 2.75 | 2.89 | 177 | 302 | 2.32 | 2.03 | 0.091 | 0.101 |
| 2002 | 2.63 | 2.75 | 191 | 290 | 2.25 | 1.97 | 0.092 | 0.103 |
| 2003 | 2.45 | 2.68 | 195 | 280 | 2.19 | 1.94 | 0.087 | 0.103 |
| 2004 | 2.22 | 2.38 | 160 | 233 | 2.39 | 2.09 | 0.083 | 0.091 |
| 2005 | 2.14 | 2.32 | 152 | 211 | 2.23 | 1.99 | 0.086 | 0.092 |
| 2006 | 2.1 | 2.3 | 173 | 211 | 2.36 | 2.08 | 0.087 | 0.091 |
| 2007 | 2.14 | 2.36 | 167 | 217 | 2.3 | 2.01 | 0.083 | 0.092 |
| 2008 | 1.95 | 2.21 | 115 | 178 | 2.18 | 1.91 | 0.069 | 0.08 |
| 2009 | 2 | 2.16 | 122 | 170 | 2.06 | 1.82 | 0.07 | 0.079 |
| 2010 | 1.8 | 2.15 | 110 | 150 | 2.17 | 1.9 | 0.065 | 0.072 |
| 2011 | 1.79 | 2.12 | 111 | 155 | 2.09 | 1.82 | 0.061 | 0.07 |
| 2012 | 1.75 | 2.19 | 101 | 158 | 2.1 | 1.82 | 0.055 | 0.065 |