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

   Clinical |
Estimate of |
  Gestation |      Freq.     Percent        Cum.
------------+-----------------------------------
         20 |          2        0.02        0.02
         22 |          1        0.01        0.03
         23 |          7        0.07        0.10
         24 |         11        0.11        0.21
         25 |          6        0.06        0.27
         26 |          6        0.06        0.33
         27 |         14        0.14        0.47
         28 |         10        0.10        0.57
         29 |         13        0.13        0.70
         30 |         29        0.29        0.99
         31 |         33        0.33        1.32
         32 |         74        0.74        2.06
         33 |         80        0.80        2.86
         34 |         80        0.80        3.66
         35 |        165        1.65        5.31
         36 |        374        3.74        9.05
         37 |        737        7.37       16.42
         38 |      1,673       16.73       33.15
         39 |      2,330       23.30       56.45
         40 |      3,272       32.72       89.17
         41 |        791        7.91       97.08
         42 |        250        2.50       99.58
         43 |         17        0.17       99.75
         44 |          1        0.01       99.76
         99 |         24        0.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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