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

    Seating |
   Position |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        897        8.97        8.97
         11 |      5,690       56.90       65.87
         12 |         42        0.42       66.29
         13 |      1,586       15.86       82.15
         18 |          1        0.01       82.16
         19 |          3        0.03       82.19
         21 |        531        5.31       87.50
         22 |        208        2.08       89.58
         23 |        518        5.18       94.76
         28 |          4        0.04       94.80
         29 |         16        0.16       94.96
         31 |         37        0.37       95.33
         32 |         22        0.22       95.55
         33 |         27        0.27       95.82
         38 |          1        0.01       95.83
         39 |         13        0.13       95.96
         41 |          1        0.01       95.97
         42 |          1        0.01       95.98
         43 |          3        0.03       96.01
         50 |         26        0.26       96.27
         51 |        166        1.66       97.93
         52 |         37        0.37       98.30
         53 |          1        0.01       98.31
         54 |          1        0.01       98.32
         55 |          9        0.09       98.41
         98 |         13        0.13       98.54
         99 |        146        1.46      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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