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

   5-minute |
Apgar score |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,359       43.59       43.59
          1 |      5,641       56.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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