Frequencies for first 10,000 rows of ekg_srvc_cd variable in pos1992 dataset :

   srv: ekg |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,640       96.40       96.40
          0 |         13        0.13       96.53
          1 |        104        1.04       97.57
          2 |        240        2.40       99.97
          3 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 May 2017