Relation between plage areas and CEA17 GSN for individual SC based on the data from the Ko (a), MD (b), and MW (c) archives, and from the CEA20 plage area composite (d). Shown are the binned values along with power-law fits. The lines are coloured according to the strength of the SC with the strength increasing from black for the weakest cycle, via dark blue, turquise, green, lime, orange, bright red to dark red for the strongest SC.