Frequencies for first 10,000 rows of vmonth variable in nhamcsopd2005 dataset :

   month of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
    january |        763        7.63        7.63
   february |      1,027       10.27       17.90
      march |        727        7.27       25.17
      april |        769        7.69       32.86
        may |        761        7.61       40.47
       june |        626        6.26       46.73
       july |        818        8.18       54.91
     august |        696        6.96       61.87
  september |      1,415       14.15       76.02
    october |        395        3.95       79.97
   november |        355        3.55       83.52
   december |      1,648       16.48      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016