Frequencies for first 10,000 rows of f_clinest variable in natlterr2006 dataset :

   Clinical |
Estimate of |
  Gestation |
  (estgest) |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,469       14.69       14.69
          1 |      8,531       85.31      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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