This paper reports observations of highly periodic flux pulsations in >30-keV electrons measured by essentially identical Los Alamos National Scientific Laboratory charged particle anaylzers on board spacecraft 1976--059, 1977--077, and 1979--053 at geostantionary orbit. Oscillations with periods in the range from ~1 min to ~10 min (Pc 4 and Pc 5) have been studied. Statistical analyses were performed using ~4.5 years of data obtained at magnetic latitudes of 4.8 ¿, 9.4 ¿, and 11.4 ¿. The statistical occurrence probabilities have been evaluated for measurements made at each of the various magnetic latitudes and for all local times. Substantial magnetic latitude and seasonal dependence are found for the flux pulsation occurrence frequency versus local time. These results are discussed in terms of previous observations and present theories of magnetic pulsation generation.