Frequencies for first 10,000 rows of vmonth variable in nhamcsopd1992 dataset :

   Month of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
    January |        269        2.69        2.69
   February |        822        8.22       10.91
      March |      1,178       11.78       22.69
      April |      1,289       12.89       35.58
        May |        829        8.29       43.87
       June |        443        4.43       48.30
       July |        976        9.76       58.06
     August |        701        7.01       65.07
  September |        298        2.98       68.05
    October |        929        9.29       77.34
   November |        767        7.67       85.01
   December |      1,499       14.99      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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