Frequencies for first 10,000 rows of birwt12 variable in natl1980 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          6        0.06        0.06
          2 |         39        0.39        0.45
          3 |         57        0.57        1.02
          4 |        138        1.38        2.40
          5 |        475        4.75        7.15
          6 |      1,719       17.19       24.34
          7 |      3,609       36.09       60.43
          8 |      2,894       28.94       89.37
          9 |        858        8.58       97.95
         10 |        169        1.69       99.64
         11 |         27        0.27       99.91
         12 |          9        0.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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