  Aims: We aim to find torus models that explain the observed high-resolution
mid-infrared (MIR) measurements of active galactic nuclei (AGN). Our goal is to
determine the general properties of the circumnuclear dusty environments.
  Methods: We used the MIR interferometric data of a sample of AGNs provided by
the instrument MIDI/VLTI and followed a statistical approach to compare the
observed distribution of the interferometric data with the distributions
computed from clumpy torus models. We mainly tested whether the diversity of
Seyfert galaxies can be described using the Standard Model idea. In addition to
line-of-sight (LOS) effects, we performed different realizations of the same
model to include possible variations that are caused by the stochastic nature
of the dusty models.
  Results: We find that our entire sample of AGNs, which contains both Seyfert
types, cannot be explained merely by an inclination effect and by including
random variations of the clouds. Instead, we find that each subset of Seyfert
type can be explained by different models, where the filling factor at the
inner radius seems to be the largest difference. For type I objects we find
that about two thirds of our objects could also be described using a dusty
torus similar to the type II objects. For the remaining third, it was not
possible to find a good description using models with high filling factors,
while we found good fits with models with low filling factors.
  Conclusions: Within our model assumptions, we did not find one single set of
model parameters that could simultaneously explain the MIR data of all 21 AGN
with LOS effects and random variations alone. We conclude that at least two
distinct cloud configurations are required to model the differences in Seyfert
galaxies, with volume-filling factors differing by a factor of about 5-10. A
continuous transition between the two types cannot be excluded.

Astrophysics of Galaxies