Frequencies for first 10,000 rows of cord variable in natlterr1997 dataset :

       Cord |
   prolapse |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         30        0.30        0.30
          2 |      9,965       99.65       99.95
          9 |          5        0.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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