Frequencies for first 10,000 rows of dgestat variable in natl1993 dataset :

Gestation - |
  Detail in |
      Weeks |      Freq.     Percent        Cum.
------------+-----------------------------------
         17 |          4        0.04        0.04
         18 |          3        0.03        0.07
         19 |          1        0.01        0.08
         20 |          1        0.01        0.09
         21 |          6        0.06        0.15
         22 |          7        0.07        0.22
         23 |          4        0.04        0.26
         24 |         14        0.14        0.40
         25 |         16        0.16        0.56
         26 |         20        0.20        0.76
         27 |         22        0.22        0.98
         28 |         23        0.23        1.21
         29 |         28        0.28        1.49
         30 |         47        0.47        1.96
         31 |         63        0.63        2.59
         32 |         87        0.87        3.46
         33 |        111        1.11        4.57
         34 |        184        1.84        6.41
         35 |        288        2.88        9.29
         36 |        425        4.25       13.54
         37 |        672        6.72       20.26
         38 |      1,375       13.75       34.01
         39 |      2,207       22.07       56.08
         40 |      2,074       20.74       76.82
         41 |      1,198       11.98       88.80
         42 |        491        4.91       93.71
         43 |        264        2.64       96.35
         44 |        170        1.70       98.05
         45 |        116        1.16       99.21
         46 |         41        0.41       99.62
         47 |         32        0.32       99.94
         99 |          6        0.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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