Frequencies for first 10,000 rows of vmonth variable in nhamcsopd2010 dataset :

   month of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
    january |        440        4.40        4.40
   february |        299        2.99        7.39
      march |        650        6.50       13.89
      april |      1,041       10.41       24.30
        may |        669        6.69       30.99
       june |        693        6.93       37.92
       july |        631        6.31       44.23
     august |      1,674       16.74       60.97
  september |      1,380       13.80       74.77
    october |        792        7.92       82.69
   november |        997        9.97       92.66
   december |        734        7.34      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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