Frequencies for first 10,000 rows of birwt12 variable in natlterr2001 dataset :

      Birth |
     Weight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          9        0.09        0.09
          2 |         66        0.66        0.75
          3 |         73        0.73        1.48
          4 |        201        2.01        3.49
          5 |        777        7.77       11.26
          6 |      2,779       27.79       39.05
          7 |      4,016       40.16       79.21
          8 |      1,747       17.47       96.68
          9 |        286        2.86       99.54
         10 |         40        0.40       99.94
         11 |          2        0.02       99.96
         12 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015