Abstract
Population pyramid is a very popular presentation of the age-sex distribution of the human population of a particular region. Its shape is influenced not only by demographical indicators, but also by many other social and political characteristics, such as birth control policy, wars, life-style etc. In the paper Clustering of population pyramids (Korenjak-C erne, Kejzar, Batagelj, Informatica, 2008) clusters of world countries with similar pyramidal shapes were obtained using Wards hierarchical clustering. The corresponding clusters shapes can offer additional insight about countries to field-related researchers. In order to get clusters where the gender and size of population are also taken into account we present data as histogram symbolic data (Billard, Diday, 2006). For their analysis we adapt the generalized Wards hierarchical clustering procedure (Batagelj, 1988). The changes of the pyramids shapes, and also changes of the countries inside main clusters will be examined for the years 1996, 2001, and 2006.