Frequencies for first 10,000 rows of amb22 variable in nhamcsopd1998 dataset :

 ambulatory |
       surg |
  procedure |
 #2 - 2 dgt |      Freq.     Percent        Cum.
------------+-----------------------------------
         00 |      9,959       99.59       99.59
         03 |          1        0.01       99.60
         42 |         11        0.11       99.71
         45 |          8        0.08       99.79
         49 |          1        0.01       99.80
         53 |          1        0.01       99.81
         57 |          1        0.01       99.82
         67 |          5        0.05       99.87
         69 |          1        0.01       99.88
         70 |          1        0.01       99.89
         75 |          1        0.01       99.90
         78 |          1        0.01       99.91
         86 |          4        0.04       99.95
         89 |          1        0.01       99.96
         91 |          1        0.01       99.97
         96 |          1        0.01       99.98
         97 |          1        0.01       99.99
         99 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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