Frequencies for first 10,000 rows of birwt12 variable in natl1972 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          2        0.02        0.02
          2 |         42        0.42        0.44
          3 |         54        0.54        0.98
          4 |        145        1.45        2.43
          5 |        521        5.21        7.64
          6 |      1,975       19.75       27.39
          7 |      3,722       37.22       64.61
          8 |      2,609       26.09       90.70
          9 |        755        7.55       98.25
         10 |        130        1.30       99.55
         11 |         15        0.15       99.70
         12 |         30        0.30      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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