Frequencies for first 10,000 rows of birwt12 variable in natl1979 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          9        0.09        0.09
          2 |         43        0.43        0.52
          3 |         58        0.58        1.10
          4 |        139        1.39        2.49
          5 |        473        4.73        7.22
          6 |      1,770       17.70       24.92
          7 |      3,738       37.38       62.30
          8 |      2,782       27.82       90.12
          9 |        771        7.71       97.83
         10 |        174        1.74       99.57
         11 |         31        0.31       99.88
         12 |         12        0.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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