Frequencies for first 10,000 rows of amb23 variable in nhamcsopd1997 dataset :

 ambulatory |
       surg |
  procedure |
 #2 - 3 dgt |      Freq.     Percent        Cum.
------------+-----------------------------------
        000 |      9,960       99.60       99.60
        129 |          1        0.01       99.61
        137 |          1        0.01       99.62
        429 |          1        0.01       99.63
        482 |          1        0.01       99.64
        494 |          1        0.01       99.65
        531 |          1        0.01       99.66
        599 |          1        0.01       99.67
        662 |          2        0.02       99.69
        671 |          1        0.01       99.70
        673 |          1        0.01       99.71
        681 |          3        0.03       99.74
        682 |          1        0.01       99.75
        690 |          2        0.02       99.77
        702 |          1        0.01       99.78
        804 |          1        0.01       99.79
        806 |          2        0.02       99.81
        819 |          2        0.02       99.83
        839 |          1        0.01       99.84
        863 |          1        0.01       99.85
        867 |          1        0.01       99.86
        887 |          4        0.04       99.90
        893 |          1        0.01       99.91
        916 |          2        0.02       99.93
        935 |          1        0.01       99.94
        938 |          1        0.01       99.95
        976 |          1        0.01       99.96
        978 |          3        0.03       99.99
        992 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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