In deriving auroral electrojet 2.5-min. magnetic activity indices for 1970, simple statistics were kept that tabulated the time and frequency of contribution of index values by each of the 11 geomagnetic observatories whose records were used in the derivation. Systematic patterns were noted in the times of most frequent observation of extreme H deviations by each station for both quiet and disturbed hours. On the average, AL was most often derived from records of stations located about 3 1/4 hours past local geomagnetic midnight, LGM (peak westward electrojet effect); a second prominent time of occurrence of extreme negative H values came at 11 1/4 hours after LGM; AU was most often derived from stations located 6 1/2 hours before LGM (peak eastward electrojet effect); and a second prominent time of occurrence of extreme positive H values came at about 6 1/4 hours after LGM. The secondary peak times of index contribution are shown to be consistent with quiet time current sources apparently equatorward of the auroral zone. The UT daily pattern of average hourly values of AU is shown to vary seasonally, being lowest in winter, intermediate during equinoctial months, and highest during summer. No clear diurnal UT dependence can be seen in disturbed hour averages of AU. The average hourly AL values for disturbed hours are not clearly differentiated by season but appear to have a broad span of higher values from 1200 to 2100 UT. A composite map is included of regions within which auroral electrojet currents would produce the systematic extreme H deviations revealed in the derivation of 1970 AE(11). Preliminary analyses of AE indices for 1966 through 1971 give results that agree with these conclusions.