Frequencies for first 10,000 rows of vmonth variable in nhamcsopd1996 dataset :

   month of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
    January |        869        8.69        8.69
   February |        781        7.81       16.50
      March |        958        9.58       26.08
      April |        886        8.86       34.94
        May |        782        7.82       42.76
       June |        877        8.77       51.53
       July |        911        9.11       60.64
     August |        867        8.67       69.31
  September |      1,029       10.29       79.60
    October |        943        9.43       89.03
   November |        519        5.19       94.22
   December |        578        5.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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