Frequencies for first 10,000 rows of vmonth variable in nhamcsopd2009 dataset :

   month of |
      visit |      Freq.     Percent        Cum.
------------+-----------------------------------
    january |        894        8.94        8.94
   february |        452        4.52       13.46
      march |        801        8.01       21.47
      april |      1,107       11.07       32.54
        may |        899        8.99       41.53
       june |      1,203       12.03       53.56
       july |        861        8.61       62.17
     august |        377        3.77       65.94
  september |      1,048       10.48       76.42
    october |      1,012       10.12       86.54
   november |        814        8.14       94.68
   december |        532        5.32      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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