Frequencies for first 10,000 rows of dgestat variable in natlterr1995 dataset :

Gestation - |
  Detail in |
      Weeks |      Freq.     Percent        Cum.
------------+-----------------------------------
         20 |          1        0.01        0.01
         21 |          2        0.02        0.03
         22 |          1        0.01        0.04
         23 |          7        0.07        0.11
         24 |          9        0.09        0.20
         25 |          7        0.07        0.27
         26 |         13        0.13        0.40
         27 |         15        0.15        0.55
         28 |         14        0.14        0.69
         29 |         23        0.23        0.92
         30 |         34        0.34        1.26
         31 |         65        0.65        1.91
         32 |         76        0.76        2.67
         33 |         92        0.92        3.59
         34 |        131        1.31        4.90
         35 |        251        2.51        7.41
         36 |        475        4.75       12.16
         37 |        916        9.16       21.32
         38 |      1,807       18.07       39.39
         39 |      2,394       23.94       63.33
         40 |      2,219       22.19       85.52
         41 |        990        9.90       95.42
         42 |        338        3.38       98.80
         43 |        101        1.01       99.81
         44 |         10        0.10       99.91
         45 |          2        0.02       99.93
         47 |          1        0.01       99.94
         99 |          6        0.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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