Currently and in season's 2013-14, 2014-15, among the league's top half we have had the most goals scored against by a significant margin.
Final position 2013-14: 2nd
GA: 37
Conceded more than Olympiakos, Atromitos, Panathinaikos, Asteras and Panaitolikos.
Final position 2014-15: 3rd
GA: 42
Conceded more than Olympiakos, Panathinaikos, Asteras, Atromitos, Giannina, Panaitolikos, Xanthi, Platanias, Kalloni, Levadiakos and Kerkyra.
Current Position 2015-16: 4th
GA: 27
Conceded more than Olympiakos, AEK, Panathinaikos, Panionios, Asteras, Panaitolikos, Iraklis, Xanthi, Platanias, Atromitos and Veria.
It's been this season we've played a back 3, requiring more defenders and we still haven't made improving our back line a priority. Aside from Chatzisaias (who basically replaced Costa anyway) the club has paid almost zero attention to this, choosing instead using makeshift central defenders. We've become way too easy to score against it's a joke.