Frequencies for intr_vbx variable in fmli132 dataset :

   intr_vbx |      Freq.     Percent        Cum.
------------+-----------------------------------
          A |      6,216       91.93       91.93
          B |        201        2.97       94.90
          D |        345        5.10      100.00
------------+-----------------------------------
      Total |      6,762      100.00

by Jean Roth , jroth@nber.org , 17 Mar 2016