  We use the open clusters (OCs) with known parameters available in the WEBDA
database and in recently published papers to derive properties related to the
disk structure. The sample totals 654 OCs, consisting basically of Trumpler
types I to III clusters. Because of the completeness effects, the observed
radial distribution of OCs with respect to Galactocentric distance does not
follow the expected exponential profile. We simulate the effects of
completeness assuming that the observed distribution of the number of OCs with
a given number of stars above the background, measured in a restricted zone
outside the Solar circle, is representative of the intrinsic distribution of
OCs throughout the Galaxy. As a result we derive completeness-corrected radial
distributions which agree with exponential disks throughout the observed
Galactocentric distance range 5--14\,kpc, with scale lengths in the range $1.5
- 1.9\,kpc$. In particular we retrieve the expected exponential-disk radial
profile for the highly depleted regions internal to the Solar circle.
Extrapolation of the completeness-corrected radial distributions down to the
Galactic center indicates a total number of OCs in the range $\rm(1.8 -
3.7)\times10^5$. These estimates are upper-limits because they do not take into
account depletion in the number of OCs by dynamical effects in the inner parts
of the Galaxy. The observed and completeness-corrected age-distributions of the
OCs can be fitted by a combination of two exponential-decay profiles
characterized by age scales of $\rm\sim100\,Myr$ and $\rm\sim1.9\,Gyr$,
respectively. This rules out evolutionary scenarios based on constant
star-formation and OC-disruption rates. We estimate that 3.4--8\% of the
embedded clusters do actually emerge from the parent molecular clouds as OCs.
