  In this work we apply techniques and modus operandi typical of Statistical
Mechanics to a large dataset about key social quantifiers and compare the
resulting behaviours of five European nations, namely France, Germany, Italy,
Spain and Switzerland. The social quantifiers considered are $i.$ the evolution
of the number of autochthonous marriages (i.e. between two natives) within a
given territorial district and $ii.$ the evolution of the number of mixed
marriages (i.e. between a native and an immigrant) within a given territorial
district. Our investigations are twofold. From a theoretical perspective, we
develop novel techniques, complementary to classical methods (e.g. historical
series and logistic regression), in order to detect possible collective
features underlying the empirical behaviours; from an experimental perspective,
we evidence a clear outline for the evolution of the social quantifiers
considered. The comparison between experimental results and theoretical
predictions is excellent and allows speculating that France, Italy and Spain
display a certain degree of {\em internal heterogeneity}, that is not found in
Germany and Switzerland; such heterogeneity, quite mild in France and in Spain,
is not negligible in Italy and highlights quantitative differences in the
customs of Northern and Southern regions. These findings may suggest the
persistence of two culturally distinct communities, long-term lasting heritages
of different and well-established cultures.
