The top hundred surnames in Wales
A modern-day survey has been conducted by Michael Williams and the results tabulated in his Researching Local History (1996). The following table shows the occurrences of the top hundred Welsh names in thousands totalled from the six British Telecom telephone directories for Wales in 1986.
The above is a headlist of Welsh-language surnames - it excludes English-language surnames like Smith. If Smith had been included, it would have been in 13th place and Green 38th. In most cases, all variants of surnames are combined, e.g. Pierce, Pearse, Pearce.
The above table appears in Michael A Williams Researching local history - the human journey and is reproduced with kind permission of the author. Copyright © Michael A Williams, 1996. Permission is currently being sought from the publisher as well.
This may be compared with the detailed historical analysis in John and Sheila Rowlands' The Surnames of Wales (Federation of Family History Societies. 1996), pages 43-44. Their findings are based on a comprehensive survey of all the surnames which were recorded in the marriage registers of all parishes in Wales for the period 1813-1837. The size of their sample is estimated at 30-40% of the potential population.
It is noticeable that the "top ten" names are the same in modern times (Williams) as in the period 1813-1837 (Rowlands and Rowlands) and are in the same order except that Thomas was in fourth place in the earlier period, slightly ahead of Evans in the ranking.
The Rowlands also analysed Surnames which are only occasionally absent, Surnames with a strong regional presence and Low incidence surnames with strong local presence. They are now (2012) working towards a second edition of The Surnames of Wales.