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

carburetion |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      4,748       47.48       47.48
          1 |          3        0.03       47.51
          2 |         21        0.21       47.72
          3 |          3        0.03       47.75
          4 |         17        0.17       47.92
          F |      5,078       50.78       98.70
          T |        114        1.14       99.84
          Z |         16        0.16      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Oct 2016