Frequencies for first 10,000 rows of vmonth variable in namcs1998 dataset :

   month of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
    January |      1,004       10.04       10.04
   February |      1,001       10.01       20.05
      March |        885        8.85       28.90
      April |        787        7.87       36.77
        May |        830        8.30       45.07
       June |      1,038       10.38       55.45
       July |        756        7.56       63.01
     August |        686        6.86       69.87
  September |        999        9.99       79.86
    October |        736        7.36       87.22
   November |        601        6.01       93.23
   December |        677        6.77      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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