Frequencies for first 10,000 rows of seat_pos variable in person dataset :

    SEATING |
   POSITION |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        743        7.43        7.43
         11 |      5,336       53.36       60.79
         12 |        141        1.41       62.20
         13 |      1,944       19.44       81.64
         18 |         13        0.13       81.77
         19 |         16        0.16       81.93
         21 |        446        4.46       86.39
         22 |        191        1.91       88.30
         23 |        491        4.91       93.21
         28 |         19        0.19       93.40
         29 |         21        0.21       93.61
         31 |         24        0.24       93.85
         32 |         15        0.15       94.00
         33 |         27        0.27       94.27
         38 |          2        0.02       94.29
         39 |          3        0.03       94.32
         42 |          1        0.01       94.33
         43 |          1        0.01       94.34
         50 |         15        0.15       94.49
         51 |        263        2.63       97.12
         52 |         42        0.42       97.54
         53 |         26        0.26       97.80
         54 |          5        0.05       97.85
         55 |         11        0.11       97.96
         99 |        204        2.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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