Frequencies for first 10,000 rows of totdiag variable in namcs1996 dataset :

 total # of |
diagnostic/ |
  screening |
   services |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,806       28.06       28.06
          1 |      3,816       38.16       66.22
          2 |      1,808       18.08       84.30
          3 |        788        7.88       92.18
          4 |        399        3.99       96.17
          5 |        173        1.73       97.90
          6 |         94        0.94       98.84
          7 |         68        0.68       99.52
          8 |         27        0.27       99.79
          9 |         14        0.14       99.93
         10 |          6        0.06       99.99
         12 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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