In every culture there are names that appear more commonly than others - John Smith, Jan Jansen and so on. The extent of the variation of names, and the frequency of those most and least common, will affect choices when processing names for, for example, matching, householding etc.
In some cultures parents are trying increasingly to give their children uncommon names. In their book, *The Narcissism Epidemic" (2009), in Chapter 11, "Seven Billion Kinds of Special," Jean Twenge and Keith Campbell plot the falling trend in giving babies common names. From 1945 to 2006, the percentage of babies given one of the ten most popular names has decreased from 34% to 9% for boys and from 23% to 8% for girls.
In England and Wales 5.7% of people share the most common 10 surnames. In 2000 almost 16000 people shared the full name David Jones.
France has over 900000 different surnames.
Belgium has the greatest number measured per inhabitant, and Italy has the best spread of names, with only 0.67% of the population sharing the top 10 surnames.
Comparatively fewer surnames exist in Denmark, Spain and Sweden where the top 10 names are shared by 25.93%, 19.65% and 19.5% of the population respectively.
In Vietnam the top 10 names are shared by 82.9% of the population.
In China the top 100 names are shared by 87% of the population, so that parents are very inventive with given names to try to provide a unique moniker for their offspring
In Korea the entire population shares no more than 300 surnames, with the majority sharing just three: Kim, Pak and Yi.
In the 2014 Indian elections, in the state of Uttar Pradesh, 12 million of the 134 million voters had Ram somewhere in their name. In Andhra Pradesh, the name Srinivas was spelt in 600 different ways. (Source)