Lists the polling firms of a popPolls object.
Value
A data.table with one row per firm and the columns firm,
polls (number of polls), first and last (date of the first and the
last poll), sampleSize (median sample size) and spellings (the names
the firm is published under, see popRenameFirms()), sorted by the number
of polls.
Examples
if (FALSE) { # \dontrun{
popFirms(popRead('DE-parliament'))
} # }