Frequencies for first 10,000 rows of proc2 variable in nhamcsed1996 dataset :

      other |
  procedure |
         #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
       0000 |      9,988       99.88       99.88
       3931 |          1        0.01       99.89
       4292 |          1        0.01       99.90
       6816 |          1        0.01       99.91
       8604 |          2        0.02       99.93
       8737 |          1        0.01       99.94
       8965 |          1        0.01       99.95
       9142 |          1        0.01       99.96
       9399 |          1        0.01       99.97
       9905 |          1        0.01       99.98
       9999 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016