Frequencies for first 10,000 rows of forcep variable in natlterr1999 dataset :

    Forceps |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         44        0.44        0.44
          2 |      9,953       99.53       99.97
          9 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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