Frequencies for first 10,000 rows of prov2135 variable in pos1997 dataset :

   srv: ekg |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,456       94.56       94.56
          0 |         35        0.35       94.91
          1 |        144        1.44       96.35
          2 |        361        3.61       99.96
          3 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016