Frequencies for first 10,000 rows of birwt12 variable in natl1973 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          9        0.09        0.09
          2 |         50        0.50        0.59
          3 |         60        0.60        1.19
          4 |        158        1.58        2.77
          5 |        503        5.03        7.80
          6 |      1,918       19.18       26.98
          7 |      3,753       37.53       64.51
          8 |      2,629       26.29       90.80
          9 |        718        7.18       97.98
         10 |        148        1.48       99.46
         11 |         20        0.20       99.66
         12 |         34        0.34      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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