Same as Fig. 6, but for the plage area series for MW data by Bertello et al. (2010, a); MW data by Ermolli et al.(2009b, b); MW data by Foukal(1996, c); MW and SP data by Foukal(2002, d); MW data by Tlatov et al. (2009, e); and for MM, MW, and BB data by SGD (f);. The series in panels b, c, and f have daily values, while the others only have annual mean values. The Bertello et al. (2010) series, which is a Ca II K emission index series, was linearly scaled to match the plage areas from our MW data (see Sect. 2).