Frequency is, quite simply, how often any particular name is given. This is the most common feature in other baby name materials, almost all of which provide a list of “The Most Popular” baby names for a particular time period. By definition, a name that tops these lists is not very unique.

In order to measure frequency you have to look at the percentage of children who are given a specific name at a specific time. As time has passed, more and more names have appeared in the US. The two reasons for this phenomenon are cultural enrichment, which happens as immigration brings new names into our cultural mix, and more venturesome parents, who increasingly leave traditional naming restrictions behind.

Since 1900, the number of names in use has risen roughly twelvefold; the US population, however, has less than quadrupled. Since many more names per child are now in circulation, the absolute frequency of all but the most popular names has been declining over the years.