Frequencies for first 10,000 rows of monitor variable in natl1990 dataset :

 Electronic |
      fetal |
 monitoring |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      7,539       75.39       75.39
          2 |      2,417       24.17       99.56
          9 |         44        0.44      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016