Search Details
Word: ppm
(lookup in dictionary)
(lookup usage)
Dates: all
Stats:
Normalized population density
(?)
for word "ppm":
Population density of a word is computed by dividing the number of
occurrences of that word by the total number of occurrences of all words.
Normalized population density is computed by dividing the population density
of a word for a given year by the population density of that word across all years.
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