Frequencies for a3 variable in midrvacc dataset :

         a3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        284       61.21       61.21
          1 |          1        0.22       61.42
          2 |          5        1.08       62.50
          3 |          3        0.65       63.15
          4 |          4        0.86       64.01
          5 |          6        1.29       65.30
          7 |          2        0.43       65.73
          8 |         11        2.37       68.10
          9 |          5        1.08       69.18
         10 |          5        1.08       70.26
         11 |          9        1.94       72.20
         12 |          9        1.94       74.14
         13 |         11        2.37       76.51
         14 |         12        2.59       79.09
         15 |         12        2.59       81.68
         16 |          8        1.72       83.41
         17 |          5        1.08       84.48
         18 |          5        1.08       85.56
         19 |         10        2.16       87.72
         20 |         10        2.16       89.87
         21 |          6        1.29       91.16
         22 |          6        1.29       92.46
         23 |          4        0.86       93.32
         24 |          3        0.65       93.97
         25 |          4        0.86       94.83
         26 |          2        0.43       95.26
         27 |          4        0.86       96.12
         28 |          6        1.29       97.41
         29 |          3        0.65       98.06
         30 |          2        0.43       98.49
         31 |          2        0.43       98.92
         32 |          1        0.22       99.14
         34 |          1        0.22       99.35
         36 |          1        0.22       99.57
         39 |          1        0.22       99.78
         43 |          1        0.22      100.00
------------+-----------------------------------
      Total |        464      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016