The annual variations of observed am index and inferred power input to the magnetosphere, P _α , comparing the solstices in particular. (a) the daily sunspot number, R; (b) the normalised average am index 〈am〉_F/〈am〉_yr, where 〈am〉_F is the average am in 36 equal-bin widths of fraction of year, F, in each year and 〈am〉_yr is the average am for that year, color-coded as a function of F and year; (c) the corresponding plot for the power input to the magnetosphere 〈P _α 〉_F/〈P _α 〉_yr; (d) a comparison of the means of am in quarter-year intervals around the June and December solstices, 〈am〉_jun and 〈am〉_dec respectively: the annual value of the ratio r _sol(am) is plotted as red/blue bars for years when it was positive/negative, respectively, where r _sol(am) = (〈am〉_jun − 〈am〉_dec)/(〈am〉_jun + 〈am〉_dec); (e) a comparison of the corresponding ratio for power input to the magnetosphere r _sol(P _α ) = (〈P _α 〉_jun − 〈P _α 〉_dec)/(〈P _α 〉_jun + 〈P _α 〉_dec). (f) shows the difference, r _sol(am) − r _sol(P _α ).