Frequencies for first 10,000 rows of vmonth variable in nhamcsopd2006 dataset :

   month of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
    January |      1,106       11.06       11.06
   February |        509        5.09       16.15
      March |      1,037       10.37       26.52
      April |        859        8.59       35.11
        May |      1,148       11.48       46.59
       June |        764        7.64       54.23
       July |        673        6.73       60.96
     August |      1,250       12.50       73.46
  September |      1,090       10.90       84.36
    October |        765        7.65       92.01
   November |        504        5.04       97.05
   December |        295        2.95      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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