Frequencies for mod_year variable in person dataset :

 Model Year |      Freq.     Percent        Cum.
------------+-----------------------------------
         12 |          1        0.08        0.08
         53 |          2        0.15        0.23
         55 |          2        0.15        0.38
         59 |          1        0.08        0.45
         61 |          6        0.45        0.91
         62 |          8        0.61        1.51
         63 |         21        1.59        3.10
         64 |         29        2.19        5.30
         65 |         29        2.19        7.49
         66 |         52        3.93       11.42
         67 |         99        7.49       18.91
         68 |         54        4.08       23.00
         69 |         91        6.88       29.88
         70 |         74        5.60       35.48
         71 |         86        6.51       41.98
         72 |         82        6.20       48.18
         73 |        105        7.94       56.13
         74 |         60        4.54       60.67
         75 |         26        1.97       62.63
         76 |         93        7.03       69.67
         77 |         79        5.98       75.64
         78 |         52        3.93       79.58
         79 |          3        0.23       79.80
         99 |         11        0.83       80.64
          . |        256       19.36      100.00
------------+-----------------------------------
      Total |      1,322      100.00

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