Frequencies for pmcycl_ds variable in parkwork dataset :

 Motorcycle |
     Engine |
Displacemen |
     t (CC) |      Freq.     Percent        Cum.
------------+-----------------------------------
        362 |          1        0.09        0.09
        996 |          1        0.09        0.19
        998 |          1        0.09        0.28
       1170 |          1        0.09        0.38
       1584 |          5        0.47        0.85
          . |      1,055       99.15      100.00
------------+-----------------------------------
      Total |      1,064      100.00

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