Frequencies for seat_pos variable in person dataset :

    SEATING |
   POSITION |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        246       19.19       19.19
         11 |        713       55.62       74.80
         12 |          1        0.08       74.88
         13 |        187       14.59       89.47
         21 |         73        5.69       95.16
         22 |         19        1.48       96.65
         23 |         36        2.81       99.45
         28 |          2        0.16       99.61
         51 |          3        0.23       99.84
         52 |          2        0.16      100.00
------------+-----------------------------------
      Total |      1,282      100.00

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