The average profile of Forbush decreases, produced by eastern-, central-and westernregion solar flares is obtained separately by superposed epoch analysis for the periods [1966][1967][1968][1969] (qA < 0) and 1971-1979 (qA > 0). It is observed that the recovery of an average Forbush decrease from the maximum depression level is faster for the situation qA > 0 than for the situation qA < O. This is in accordance with expectations from the drift theory. It is also observed that the drift effect is more pronounced for western-flare Forbush decreases which, of course, have a smaller magnitude compared to eastern-and central-flare Forbush decreases.
The average profiles of simple and complex type Forbush decreases are also obtained separately for three periods 1965-1979, 1971-1979, and 1981-1987. It is found that the average profiles of simple and complex type Forbush decreases observed during the period 1965-1969 and 1971-1979 are quite in agreement with drift theory. The anomalous behavior of average Forbush-decrease profiles during the period 1981-1987, especially in simple type Forbush decreases, is also explained by a drift current sheet tilt model.