Frequencies for first 10,000 rows of amb22 variable in namcs1999 dataset :

 ambulatory |
       surg |
  procedure |
 #2 - 2 dgt |      Freq.     Percent        Cum.
------------+-----------------------------------
         00 |      9,952       99.52       99.52
         08 |          2        0.02       99.54
         13 |          1        0.01       99.55
         21 |          1        0.01       99.56
         27 |          1        0.01       99.57
         45 |          3        0.03       99.60
         48 |          1        0.01       99.61
         67 |          1        0.01       99.62
         69 |          1        0.01       99.63
         70 |          1        0.01       99.64
         81 |          3        0.03       99.67
         83 |          1        0.01       99.68
         86 |         26        0.26       99.94
         93 |          2        0.02       99.96
         96 |          2        0.02       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