Frequencies for first 10,000 rows of proc2 variable in nhamcsed1997 dataset :

      other |
  procedure |
         #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
       0000 |      9,989       99.89       99.89
       3404 |          1        0.01       99.90
       3893 |          1        0.01       99.91
       4523 |          1        0.01       99.92
       5425 |          1        0.01       99.93
       8623 |          1        0.01       99.94
       8906 |          2        0.02       99.96
       897- |          1        0.01       99.97
       9419 |          1        0.01       99.98
       9449 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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