Frequencies for first 10,000 rows of month variable in nsrd dataset :

      Month |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        770        7.70        7.70
          2 |        770        7.70       15.40
          3 |        770        7.70       23.10
          4 |        769        7.69       30.79
          5 |        769        7.69       38.48
          6 |        769        7.69       46.17
          7 |        769        7.69       53.86
          8 |        769        7.69       61.55
          9 |        769        7.69       69.24
         10 |        769        7.69       76.93
         11 |        769        7.69       84.62
         12 |        769        7.69       92.31
     Annual |        769        7.69      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 15 Jun 2016