have only become more so over time further analysis of what exactly is driving the diversitylike the increase of alternate spellingsis left to the reader the "last letterrevolution in baby name researcher laura wattenberg pointed out on her website (http//www babynamewizard comthat the distribution of boy names by final letter has changed significantly over the last years to see thisi first aggregate all of the births in the full data set by yearsexand final letterextract last letter from name column get_last_letter lambda xx[- last_letters names name map(get_last_letterlast_letters name 'last_lettertable names pivot_table('births'rows=last_letterscols=['sex''year']aggfunc=sumtheni select out three representative years spanning the history and print the first few rowsin [ ]subtable table reindex(columns=[ ]level='year'in [ ]subtable head(out[ ]sex year last_letter nan nextnormalize the table by total births to compute new table containing proportion of total births for each sex ending in each letterin [ ]subtable sum(out[ ]sex year in [ ]letter_prop subtable subtable sum(astype(floatwith the letter proportions now in handi can make bar plots for each sex broken down by year see figure - import matplotlib pyplot as plt introductory examples www it-ebooks info