Good point. UK & Denmark both have formal de jure opt outs, negotiated on launch of the EUR project. Sweden is a de facto opt out. By not entering the ERM trial

Good point. UK & Denmark both have formal de jure opt outs, negotiated on launch of the EUR project. Sweden is a de facto opt out. By not entering the ERM trial period and managing SEK into a band with EUR, SE never enters the Eurozone.