Frequencies for a1 variable in miacc dataset :

         a1 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        199       51.82       51.82
          1 |          3        0.78       52.60
          2 |          9        2.34       54.95
          3 |          4        1.04       55.99
          4 |          5        1.30       57.29
          5 |          4        1.04       58.33
          6 |          8        2.08       60.42
          7 |          1        0.26       60.68
          8 |          9        2.34       63.02
          9 |          5        1.30       64.32
         10 |          7        1.82       66.15
         11 |          7        1.82       67.97
         12 |          5        1.30       69.27
         13 |          8        2.08       71.35
         14 |          9        2.34       73.70
         15 |          8        2.08       75.78
         16 |          8        2.08       77.86
         17 |          6        1.56       79.43
         18 |          7        1.82       81.25
         19 |          6        1.56       82.81
         20 |         12        3.12       85.94
         21 |          8        2.08       88.02
         22 |          8        2.08       90.10
         23 |          4        1.04       91.15
         24 |          5        1.30       92.45
         25 |          4        1.04       93.49
         26 |          5        1.30       94.79
         27 |          5        1.30       96.09
         28 |          1        0.26       96.35
         29 |          2        0.52       96.87
         30 |          1        0.26       97.14
         32 |          2        0.52       97.66
         34 |          2        0.52       98.18
         35 |          1        0.26       98.44
         36 |          2        0.52       98.96
         38 |          1        0.26       99.22
         40 |          2        0.52       99.74
         42 |          1        0.26      100.00
------------+-----------------------------------
      Total |        384      100.00

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