Frequencies for first 10,000 rows of birwt12 variable in natl1987 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         10        0.10        0.10
          2 |         46        0.46        0.56
          3 |         65        0.65        1.21
          4 |        170        1.70        2.91
          5 |        483        4.83        7.74
          6 |      1,681       16.81       24.55
          7 |      3,713       37.13       61.68
          8 |      2,768       27.68       89.36
          9 |        867        8.67       98.03
         10 |        164        1.64       99.67
         11 |         24        0.24       99.91
         12 |          9        0.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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