Frequencies for first 10,000 rows of dgestat variable in natl2001 dataset :

Gestation - |
  Detail in |
      Weeks |      Freq.     Percent        Cum.
------------+-----------------------------------
         17 |          1        0.01        0.01
         18 |          2        0.02        0.03
         20 |          3        0.03        0.06
         21 |          9        0.09        0.15
         22 |          8        0.08        0.23
         23 |          7        0.07        0.30
         24 |         13        0.13        0.43
         25 |         19        0.19        0.62
         26 |         19        0.19        0.81
         27 |         13        0.13        0.94
         28 |         30        0.30        1.24
         29 |         27        0.27        1.51
         30 |         38        0.38        1.89
         31 |         57        0.57        2.46
         32 |         87        0.87        3.33
         33 |         96        0.96        4.29
         34 |        200        2.00        6.29
         35 |        319        3.19        9.48
         36 |        541        5.41       14.89
         37 |        957        9.57       24.46
         38 |      1,980       19.80       44.26
         39 |      2,413       24.13       68.39
         40 |      1,670       16.70       85.09
         41 |        751        7.51       92.60
         42 |        297        2.97       95.57
         43 |        178        1.78       97.35
         44 |        128        1.28       98.63
         45 |         60        0.60       99.23
         46 |         44        0.44       99.67
         47 |         20        0.20       99.87
         99 |         13        0.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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