Frequencies for first 10,000 rows of a2 variable in midrvacc dataset :

         a2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      6,708       67.08       67.08
          1 |         54        0.54       67.62
          2 |         72        0.72       68.34
          3 |         49        0.49       68.83
          4 |         62        0.62       69.45
          5 |         67        0.67       70.12
          6 |         76        0.76       70.88
          7 |         84        0.84       71.72
          8 |         82        0.82       72.54
          9 |         93        0.93       73.47
         10 |        107        1.07       74.54
         11 |        139        1.39       75.93
         12 |        134        1.34       77.27
         13 |        142        1.42       78.69
         14 |        153        1.53       80.22
         15 |        159        1.59       81.81
         16 |        155        1.55       83.36
         17 |        159        1.59       84.95
         18 |        169        1.69       86.64
         19 |        153        1.53       88.17
         20 |        155        1.55       89.72
         21 |        145        1.45       91.17
         22 |        135        1.35       92.52
         23 |        114        1.14       93.66
         24 |        104        1.04       94.70
         25 |        103        1.03       95.73
         26 |         85        0.85       96.58
         27 |         63        0.63       97.21
         28 |         56        0.56       97.77
         29 |         34        0.34       98.11
         30 |         44        0.44       98.55
         31 |         29        0.29       98.84
         32 |         19        0.19       99.03
         33 |         19        0.19       99.22
         34 |         13        0.13       99.35
         35 |         14        0.14       99.49
         36 |         14        0.14       99.63
         37 |         10        0.10       99.73
         38 |          3        0.03       99.76
         39 |          2        0.02       99.78
         40 |          4        0.04       99.82
         42 |          2        0.02       99.84
         43 |          1        0.01       99.85
         44 |          5        0.05       99.90
         46 |          1        0.01       99.91
         48 |          2        0.02       99.93
         50 |          1        0.01       99.94
         59 |          1        0.01       99.95
         67 |          1        0.01       99.96
         68 |          1        0.01       99.97
         79 |          1        0.01       99.98
         94 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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