Frequencies for first 10,000 rows of birwt12 variable in natl1981 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          6        0.06        0.06
          2 |         25        0.25        0.31
          3 |         67        0.67        0.98
          4 |        136        1.36        2.34
          5 |        468        4.68        7.02
          6 |      1,680       16.80       23.82
          7 |      3,808       38.08       61.90
          8 |      2,796       27.96       89.86
          9 |        807        8.07       97.93
         10 |        168        1.68       99.61
         11 |         30        0.30       99.91
         12 |          9        0.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016