Frequencies for first 10,000 rows of geste variable in linkco1991us_num dataset :

   Clinical |
estimate of |
  gestation |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,355       43.55       43.55
          1 |      5,645       56.45      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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