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

   Clinical |
Estimate of |
  Gestation |      Freq.     Percent        Cum.
------------+-----------------------------------
         17 |          1        0.01        0.01
         18 |          1        0.01        0.02
         19 |          2        0.02        0.04
         20 |          4        0.04        0.08
         21 |          2        0.02        0.10
         22 |          6        0.06        0.16
         23 |         16        0.16        0.32
         24 |         12        0.12        0.44
         25 |         12        0.12        0.56
         26 |         21        0.21        0.77
         27 |         25        0.25        1.02
         28 |         29        0.29        1.31
         29 |         19        0.19        1.50
         30 |         27        0.27        1.77
         31 |         36        0.36        2.13
         32 |         55        0.55        2.68
         33 |         65        0.65        3.33
         34 |        142        1.42        4.75
         35 |        219        2.19        6.94
         36 |        435        4.35       11.29
         37 |        796        7.96       19.25
         38 |      1,670       16.70       35.95
         39 |      2,472       24.72       60.67
         40 |      2,942       29.42       90.09
         41 |        836        8.36       98.45
         42 |        138        1.38       99.83
         43 |          7        0.07       99.90
         45 |          1        0.01       99.91
         99 |          9        0.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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