Frequencies for first 10,000 rows of uop_monit variable in natlterr2006 dataset :

 Electronic |
      Fetal |
 Monitoring |
          U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      4,151       41.51       41.51
          2 |        624        6.24       47.75
          9 |      1,500       15.00       62.75
          . |      3,725       37.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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