Frequencies for first 10,000 rows of f_ab_surfac variable in natlterr2005 dataset :

 Surfactant |
          R |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      6,264       62.64       62.64
          1 |      3,736       37.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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