Frequencies for first 10,000 rows of birwt12 variable in natl1988 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         17        0.17        0.17
          2 |         43        0.43        0.60
          3 |         60        0.60        1.20
          4 |        135        1.35        2.55
          5 |        505        5.05        7.60
          6 |      1,695       16.95       24.55
          7 |      3,536       35.36       59.91
          8 |      2,853       28.53       88.44
          9 |        942        9.42       97.86
         10 |        160        1.60       99.46
         11 |         29        0.29       99.75
         12 |         25        0.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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