"Figure 8: Sulphate in upland waters has declined by an average of 61 microequivalent per litre in 1989 to 29 microequivalent per litre in 2018","" "Non-marine sulphate concentrations in Upland Water Monitoring Network mountains, moorlands and heath sites, upscaled to UK, 1989 to 2018","" "","" "Notes","" "Unit","Microequivalents per litre" "","" "Year","xSO4 annual","5 year mean" "1989","60.70","64.39" "1990","60.49","64.39" "1991","69.99","64.39" "1992","65.41","64.39" "1993","65.38","64.39" "1994","62.25","60.71" "1995","63.52","60.71" "1996","69.68","60.71" "1997","56.64","60.71" "1998","51.46","60.71" "1999","43.75","42.10" "2000","40.24","42.10" "2001","42.21","42.10" "2002","36.48","42.10" "2003","47.82","42.10" "2004","44.09","37.80" "2005","37.10","37.80" "2006","43.18","37.80" "2007","32.63","37.80" "2008","32.00","37.80" "2009","31.82","33.34" "2010","38.10","33.34" "2011","32.01","33.34" "2012","30.54","33.34" "2013","34.21","33.34" "2014","25.63","25.31" "2015","23.39","25.31" "2016","22.65","25.31" "2017","25.60","25.31" "2018","29.29","25.31"