| Year | River nitrate 1992-2021 (640) (secondary axis) | River nitrate 2000-2021 (1,006) (secondary axis) | Groundwater nitrate 1992-2021 (475) | Groundwater nitrate 2000-2021 (1,025) |
|---|---|---|---|---|
| 1992 | 2.35 | 19.7 | ||
| 1993 | 2.24 | 19.55 | ||
| 1994 | 2.12 | 19.69 | ||
| 1995 | 2.08 | 20.19 | ||
| 1996 | 2.17 | 20.11 | ||
| 1997 | 2.27 | 20.95 | ||
| 1998 | 2.3 | 20.91 | ||
| 1999 | 2.07 | 20.62 | ||
| 2000 | 2.16 | 1.88 | 20.93 | 20.65 |
| 2001 | 2.2 | 1.92 | 20.44 | 20.49 |
| 2002 | 2.13 | 1.89 | 19.97 | 20.04 |
| 2003 | 2.06 | 1.84 | 20.47 | 20.34 |
| 2004 | 2.22 | 1.96 | 20.49 | 20.19 |
| 2005 | 2.08 | 1.87 | 20.04 | 20.29 |
| 2006 | 2.16 | 1.94 | 19.85 | 20.37 |
| 2007 | 2.12 | 1.87 | 20.54 | 20.7 |
| 2008 | 2.03 | 1.78 | 21.2 | 20.85 |
| 2009 | 1.91 | 1.71 | 21.12 | 20.55 |
| 2010 | 1.99 | 1.78 | 21.05 | 20.87 |
| 2011 | 1.89 | 1.69 | 19.89 | 20.06 |
| 2012 | 1.84 | 1.66 | 21.13 | 20.64 |
| 2013 | 1.99 | 1.78 | 20.48 | 20.63 |
| 2014 | 1.92 | 1.72 | 20.3 | 20.79 |
| 2015 | 1.88 | 1.69 | 20.37 | 20.91 |
| 2016 | 1.87 | 1.62 | 20.39 | 21.27 |
| 2017 | 1.87 | 1.64 | 20.08 | 20.59 |
| 2018 | 1.76 | 1.59 | 20.93 | 20.61 |
| 2019 | 1.96 | 1.7 | 20.6 | 20.28 |
| 2020 | 1.84 | 1.6 | 20.7 | 20.03 |
| 2021 | 2.02 | 1.71 | 20.86 | 20.13 |