Frequencies for first 10,000 rows of birwt12 variable in natl1969 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          7        0.07        0.07
          2 |         54        0.54        0.61
          3 |         76        0.76        1.37
          4 |        155        1.55        2.92
          5 |        568        5.68        8.60
          6 |      1,853       18.53       27.13
          7 |      3,693       36.93       64.06
          8 |      2,644       26.44       90.50
          9 |        722        7.22       97.72
         10 |        137        1.37       99.09
         11 |         16        0.16       99.25
         12 |         75        0.75      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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