Frequencies for first 10,000 rows of estgest variable in natl2008 dataset :

Obstetric/C |
    linical |
  Gestation |
   Est. RFP |
573=f_cline |
     st U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
         18 |          4        0.04        0.04
         19 |          1        0.01        0.05
         20 |          3        0.03        0.08
         21 |          7        0.07        0.15
         22 |          3        0.03        0.18
         23 |          8        0.08        0.26
         24 |         20        0.20        0.46
         25 |         17        0.17        0.63
         26 |         25        0.25        0.88
         27 |         19        0.19        1.07
         28 |         24        0.24        1.31
         29 |         27        0.27        1.58
         30 |         22        0.22        1.80
         31 |         44        0.44        2.24
         32 |         73        0.73        2.97
         33 |         86        0.86        3.83
         34 |        142        1.42        5.25
         35 |        223        2.23        7.48
         36 |        462        4.62       12.10
         37 |      1,057       10.57       22.67
         38 |      2,512       25.12       47.79
         39 |      3,219       32.19       79.98
         40 |      1,615       16.15       96.13
         41 |        349        3.49       99.62
         42 |         24        0.24       99.86
         43 |          1        0.01       99.87
         99 |         13        0.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 May 2016