Having visibility to the prevalence means, for example, you might outright block every password that's appeared 100 times or more and force the user to choose another one (there are 1,858,690 of those in the data set), strongly recommend they choose a different password where it's appeared between 20 and 99 times (there's a further 9,985,150 of those), and merely flag the record if it's in the source data less than 20 times.