LONDON (Reuters) - The number of people in Britain with surnames like Cockshott, Balls, Death and Shufflebottom -- likely the source of schoolroom laughter -- has declined by up to 75 percent in the last century.

A generic picture of an Oxford English dictionary and a thesaurus appear in this undated file photo. REUTERS/Catherine Benson

A study found the number of people with the name Cock shrank to 785 last year from 3,211 in 1881, those called Balls fell to 1,299 from 2,904 and the number of Deaths were reduced to 605 from 1,133.

People named Smellie decreased by 70 percent, Dafts by 51 percent, Gotobeds by 42 percent, Shufflebottoms by 40 percent, and Cockshotts by 34 percent, said Richard Webber, visiting professor of geography at King’s College, London.

“If you find the (absolute) number goes down, it’s either because they changed their names or they emigrated,” Webber, author of the study, told Reuters Wednesday.

He said that in many cases, people probably changed their surnames as they came to be regarded as in bad taste. “It’s because the meaning of words can change. Take the name Daft -- that as a term for a stupid is a relatively recent innovation.”

According to the Oxford English Dictionary, Daft meant “mild” or “meek” in Old English, whereas it means “foolish” today.

“That’s why there are names which people think aren’t really very pleasant names and you wonder why they persisted as long as they did.”

Webber, whose work can be seen on the website mapyourname.com, got his data for 2008 from credit card firm Experian and mapping service Geowise. He then compared it with the census of 1881.

Webber also discovered that the most popular names in Britain have not changed over the past 127 years. Last year, Smith, Jones, Williams, Brown, Taylor and Davies held the top five spots, in exactly the same order as they did a century ago.

Webber also found that between 1996 and 2008, the names Zhang, Wang, and Yang and experienced the fastest growth. Zhang rose by 4719 percent, while Wang grew by 2225 percent.