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

 Model Year |      Freq.     Percent        Cum.
------------+-----------------------------------
         10 |          1        0.01        0.01
         30 |          3        0.03        0.04
         39 |          2        0.02        0.06
         40 |          4        0.04        0.10
         42 |          3        0.03        0.13
         44 |          2        0.02        0.15
         45 |          1        0.01        0.16
         46 |          4        0.04        0.20
         47 |          4        0.04        0.24
         48 |          2        0.02        0.26
         49 |          1        0.01        0.27
         50 |         61        0.61        0.88
         51 |         12        0.12        1.00
         52 |         10        0.10        1.10
         53 |         13        0.13        1.23
         54 |         16        0.16        1.39
         55 |         44        0.44        1.83
         56 |         38        0.38        2.21
         57 |         23        0.23        2.44
         58 |         23        0.23        2.67
         59 |         45        0.45        3.12
         60 |         74        0.74        3.86
         61 |         76        0.76        4.62
         62 |        164        1.64        6.26
         63 |        252        2.52        8.78
         64 |        339        3.39       12.17
         65 |        387        3.87       16.04
         66 |        458        4.58       20.62
         67 |        508        5.08       25.70
         68 |        573        5.73       31.43
         69 |        705        7.05       38.48
         70 |        643        6.43       44.91
         71 |        657        6.57       51.48
         72 |        781        7.81       59.29
         73 |        956        9.56       68.85
         74 |        914        9.14       77.99
         75 |        738        7.38       85.37
         76 |        500        5.00       90.37
         77 |          7        0.07       90.44
         78 |          3        0.03       90.47
         79 |          3        0.03       90.50
         99 |         88        0.88       91.38
          . |        862        8.62      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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