Frequencies for first 10,000 rows of birwt12 variable in natl1971 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          6        0.06        0.06
          2 |         34        0.34        0.40
          3 |         56        0.56        0.96
          4 |        154        1.54        2.50
          5 |        552        5.52        8.02
          6 |      1,866       18.66       26.68
          7 |      3,796       37.96       64.64
          8 |      2,567       25.67       90.31
          9 |        774        7.74       98.05
         10 |        153        1.53       99.58
         11 |         18        0.18       99.76
         12 |         24        0.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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