Frequencies for first 10,000 rows of ekg_srvc_cd variable in pos1994 dataset :

   srv: ekg |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,575       95.75       95.75
          0 |         22        0.22       95.97
          1 |        124        1.24       97.21
          2 |        276        2.76       99.97
          3 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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