Frequencies for first 10,000 rows of clingest variable in natlterr1994 dataset :

   Clinical |
Estimate of |
  Gestation |      Freq.     Percent        Cum.
------------+-----------------------------------
         20 |          1        0.01        0.01
         21 |          2        0.02        0.03
         22 |          3        0.03        0.06
         23 |          6        0.06        0.12
         24 |          2        0.02        0.14
         25 |         11        0.11        0.25
         26 |         13        0.13        0.38
         27 |         18        0.18        0.56
         28 |         20        0.20        0.76
         29 |         24        0.24        1.00
         30 |         24        0.24        1.24
         31 |         37        0.37        1.61
         32 |         61        0.61        2.22
         33 |         50        0.50        2.72
         34 |         99        0.99        3.71
         35 |        171        1.71        5.42
         36 |        371        3.71        9.13
         37 |        751        7.51       16.64
         38 |      1,761       17.61       34.25
         39 |      2,252       22.52       56.77
         40 |      3,269       32.69       89.46
         41 |        741        7.41       96.87
         42 |        271        2.71       99.58
         43 |         23        0.23       99.81
         44 |          2        0.02       99.83
         99 |         17        0.17      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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