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

    SEATING |
   POSITION |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        725        7.25        7.25
         11 |      5,268       52.68       59.93
         12 |        127        1.27       61.20
         13 |      1,969       19.69       80.89
         18 |         17        0.17       81.06
         19 |         26        0.26       81.32
         21 |        484        4.84       86.16
         22 |        215        2.15       88.31
         23 |        542        5.42       93.73
         28 |         23        0.23       93.96
         29 |         28        0.28       94.24
         31 |         20        0.20       94.44
         32 |         15        0.15       94.59
         33 |         18        0.18       94.77
         39 |          9        0.09       94.86
         41 |          1        0.01       94.87
         43 |          1        0.01       94.88
         50 |         18        0.18       95.06
         51 |        202        2.02       97.08
         52 |         87        0.87       97.95
         53 |         17        0.17       98.12
         54 |          2        0.02       98.14
         55 |          6        0.06       98.20
         99 |        180        1.80      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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