Frequencies for first 10,000 rows of proc6 variable in nhamcsopd1993 dataset :

 service #6 |
  procedure |
   code - 4 |
     digits |      Freq.     Percent        Cum.
------------+-----------------------------------
       0000 |      9,993       99.93       99.93
       751- |          1        0.01       99.94
       8744 |          1        0.01       99.95
       8762 |          1        0.01       99.96
       8926 |          1        0.01       99.97
       9141 |          1        0.01       99.98
       9142 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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