  This paper presents dielectric relaxation data for organic glass-forming
liquids compiled from different groups and supplemented by new measurements.
The main quantity of interest is the "minimum slope" of the $\alpha$ dielectric
loss plotted as a function of frequency in a log-log plot (i.e., the
numerically largest slope above the loss peak frequency). The data consisting
of 347 spectra for 53 liquids show prevalence of minimum slopes close to -1/2,
corresponding to approximate square-root-time dependence of the dielectric
relaxation function at short times. The paper further studies possible
correlations between minimum slopes and: 1) Temperature quantified via the
loss-peak frequency; 2) How well an inverse power law fits data above the loss
peak; 3) Degree of time-temperature superposition; 4) Loss-peak half width; 5)
Deviation from non-Arrhenius behavior; 6) Loss strength. For the first three
points we find correlations that indicate a special status of liquids with
minimum slopes close to -1/2. For the last three points only fairly
insignificant correlations are found with the exception of large-loss liquids,
which have minimum slopes that are numerically significantly larger than 1/2
and loss peak widths that are significantly smaller than those of most other
liquids. We conclude that -- excluding large-loss liquids -- approximate $\sqrt
t$ relaxation appears to be a generic property of the $\alpha$ relaxation of
organic glass formers.
