Frequencies for first 10,000 rows of ekg_srvc_cd variable in pos2003 dataset :

   srv: ekg |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,140       91.40       91.40
          0 |         39        0.39       91.79
          1 |        237        2.37       94.16
          2 |        566        5.66       99.82
          3 |         18        0.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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