Year	mg NO3/l
2000	4.09
2001	4.16
2002	4.08
2003	4.29
2004	4.72
2005	4.53
2006	4.56
2007	4.17
2008	4.65
2009	5.39
2010	5
2011	4.97
2012	3.6
2013	4.18
2014	4.47
2015	3.77
2016	4.06
2017	3.79