Frequencies for first 10,000 rows of clingest variable in natl1994 dataset :

   Clinical |
Estimate of |
  Gestation |      Freq.     Percent        Cum.
------------+-----------------------------------
         18 |          2        0.02        0.02
         19 |          2        0.02        0.04
         20 |          6        0.06        0.10
         21 |          1        0.01        0.11
         22 |          9        0.09        0.20
         23 |          9        0.09        0.29
         24 |          9        0.09        0.38
         25 |         10        0.10        0.48
         26 |         13        0.13        0.61
         27 |         10        0.10        0.71
         28 |         24        0.24        0.95
         29 |         19        0.19        1.14
         30 |         39        0.39        1.53
         31 |         50        0.50        2.03
         32 |         48        0.48        2.51
         33 |         75        0.75        3.26
         34 |        131        1.31        4.57
         35 |        210        2.10        6.67
         36 |        406        4.06       10.73
         37 |        700        7.00       17.73
         38 |      1,397       13.97       31.70
         39 |      2,096       20.96       52.66
         40 |      3,460       34.60       87.26
         41 |        975        9.75       97.01
         42 |        250        2.50       99.51
         43 |         19        0.19       99.70
         44 |          1        0.01       99.71
         99 |         29        0.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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