Time evolution of the current-carrying helicity H_J for the ten ARs under study. Quantities for ARs productive of large eruptive and confined flares are shown in the left and right columns, respectively. Squares (bullets) indicate the solutions based on enhanced (standard) divergence freeness. The gray shaded areas mark the spread of H_J, and the black curve indicate the average values. The vertical bar marks the impulsive flare phase.