Frequencies for first 10,000 rows of prov2135 variable in pos1999 dataset :

   srv: ekg |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,372       93.72       93.72
          0 |         38        0.38       94.10
          1 |        168        1.68       95.78
          2 |        416        4.16       99.94
          3 |          6        0.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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