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

       hour |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        354        3.54        3.54
          1 |        350        3.50        7.04
          2 |        379        3.79       10.83
          3 |        226        2.26       13.09
          4 |        256        2.56       15.65
          5 |        341        3.41       19.06
          6 |        286        2.86       21.92
          7 |        391        3.91       25.83
          8 |        234        2.34       28.17
          9 |        312        3.12       31.29
         10 |        354        3.54       34.83
         11 |        380        3.80       38.63
         12 |        404        4.04       42.67
         13 |        460        4.60       47.27
         14 |        528        5.28       52.55
         15 |        544        5.44       57.99
         16 |        518        5.18       63.17
         17 |        557        5.57       68.74
         18 |        575        5.75       74.49
         19 |        536        5.36       79.85
         20 |        525        5.25       85.10
         21 |        522        5.22       90.32
         22 |        430        4.30       94.62
         23 |        445        4.45       99.07
         24 |          3        0.03       99.10
         99 |         90        0.90      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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