Frequencies for first 10,000 rows of birwt12 variable in natl1978 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          6        0.06        0.06
          2 |         28        0.28        0.34
          3 |         51        0.51        0.85
          4 |        155        1.55        2.40
          5 |        532        5.32        7.72
          6 |      1,754       17.54       25.26
          7 |      3,717       37.17       62.43
          8 |      2,711       27.11       89.54
          9 |        834        8.34       97.88
         10 |        173        1.73       99.61
         11 |         22        0.22       99.83
         12 |         17        0.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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