Frequencies for first 10,000 rows of amb22 variable in namcs2000 dataset :

 ambulatory |
       surg |
  procedure |
 #2 - 2 dgt |      Freq.     Percent        Cum.
------------+-----------------------------------
         00 |      9,979       99.79       99.79
         08 |          1        0.01       99.80
         18 |          1        0.01       99.81
         69 |          1        0.01       99.82
         79 |          1        0.01       99.83
         81 |          2        0.02       99.85
         85 |          5        0.05       99.90
         86 |          2        0.02       99.92
         89 |          1        0.01       99.93
         91 |          1        0.01       99.94
         93 |          2        0.02       99.96
         96 |          1        0.01       99.97
         97 |          1        0.01       99.98
         98 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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