Frequencies for first 10,000 rows of proc2 variable in nhamcsed1999 dataset :

      other |
  procedure |
         #2 |      Freq.     Percent        Cum.
------------+-----------------------------------
       0000 |      9,989       99.89       99.89
       3712 |          1        0.01       99.90
       3891 |          1        0.01       99.91
       3959 |          1        0.01       99.92
       3995 |          1        0.01       99.93
       4516 |          1        0.01       99.94
       8381 |          1        0.01       99.95
       8934 |          1        0.01       99.96
       8937 |          1        0.01       99.97
       9191 |          1        0.01       99.98
       9785 |          1        0.01       99.99
       9905 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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