Frequencies for first 10,000 rows of vmonth variable in nhamcsopd2007 dataset :

   month of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
    january |        891        8.91        8.91
   february |        221        2.21       11.12
      march |        569        5.69       16.81
      april |        878        8.78       25.59
        may |      1,190       11.90       37.49
       june |        594        5.94       43.43
       july |        905        9.05       52.48
     august |      1,007       10.07       62.55
  september |        601        6.01       68.56
    october |      1,573       15.73       84.29
   november |        958        9.58       93.87
   december |        613        6.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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