Frequencies for first 10,000 rows of dgestat variable in natl1998 dataset :

Gestation - |
  Detail in |
      Weeks |      Freq.     Percent        Cum.
------------+-----------------------------------
         17 |          2        0.02        0.02
         18 |          2        0.02        0.04
         19 |          1        0.01        0.05
         20 |          2        0.02        0.07
         21 |          5        0.05        0.12
         22 |          9        0.09        0.21
         23 |         14        0.14        0.35
         24 |         10        0.10        0.45
         25 |         14        0.14        0.59
         26 |         18        0.18        0.77
         27 |         28        0.28        1.05
         28 |         32        0.32        1.37
         29 |         42        0.42        1.79
         30 |         47        0.47        2.26
         31 |         59        0.59        2.85
         32 |         83        0.83        3.68
         33 |        103        1.03        4.71
         34 |        196        1.96        6.67
         35 |        303        3.03        9.70
         36 |        500        5.00       14.70
         37 |        898        8.98       23.68
         38 |      1,717       17.17       40.85
         39 |      2,249       22.49       63.34
         40 |      1,905       19.05       82.39
         41 |        929        9.29       91.68
         42 |        365        3.65       95.33
         43 |        203        2.03       97.36
         44 |        148        1.48       98.84
         45 |         49        0.49       99.33
         46 |         35        0.35       99.68
         47 |         28        0.28       99.96
         99 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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