baby-names.csv contains the top 1000 girl and boy baby names from 1880 to 2009. This data was aggregated from the data made available from the social security administration. If you want to recreate it yourself, run the files
3-clean.r in order. You will need both R and ruby.
Since the 1960's the percentage of babies with names in the top 1000 has been shrinking, to it's current level of 80% of boys and 67% of girls.