Frequencies for first 10,000 rows of birwt12 variable in natl1977 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          8        0.08        0.08
          2 |         34        0.34        0.42
          3 |         69        0.69        1.11
          4 |        139        1.39        2.50
          5 |        512        5.12        7.62
          6 |      1,826       18.26       25.88
          7 |      3,667       36.67       62.55
          8 |      2,703       27.03       89.58
          9 |        822        8.22       97.80
         10 |        162        1.62       99.42
         11 |         35        0.35       99.77
         12 |         23        0.23      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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