Frequencies for first 10,000 rows of birwt12 variable in natl1976 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          5        0.05        0.05
          2 |         21        0.21        0.26
          3 |         61        0.61        0.87
          4 |        129        1.29        2.16
          5 |        546        5.46        7.62
          6 |      1,787       17.87       25.49
          7 |      3,771       37.71       63.20
          8 |      2,671       26.71       89.91
          9 |        808        8.08       97.99
         10 |        167        1.67       99.66
         11 |         22        0.22       99.88
         12 |         12        0.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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