Number of objects versus rotational rate in cycles/day: two different samples are plotted. Black bars: the entire sample considering that all the light curves are single-peaked (number of objects (N) = 115). Gray bars: the entire sample considering double-period light curves. A Maxwellian fit to the entire sample assuming a single period distribution gives a mean rotational period of 5.35 h (σ = 2.813 ± 0.262, continuous black line). The Maxwellian fit of the second sample gives a mean rotational period of 10.11 h (σ = 1.488 ± 0.139, continuous gray line).