Frequencies for pminute variable in parkwork dataset :

 crash time |
   (minute) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         53        4.86        4.86
          1 |         13        1.19        6.05
          2 |         14        1.28        7.33
          3 |         16        1.47        8.80
          4 |         16        1.47       10.27
          5 |         23        2.11       12.37
          6 |          6        0.55       12.92
          7 |          8        0.73       13.66
          8 |         21        1.92       15.58
          9 |         22        2.02       17.60
         10 |         37        3.39       20.99
         11 |          5        0.46       21.45
         12 |         21        1.92       23.37
         13 |         18        1.65       25.02
         14 |          7        0.64       25.66
         15 |         35        3.21       28.87
         16 |         11        1.01       29.88
         17 |         22        2.02       31.90
         18 |          4        0.37       32.26
         19 |          8        0.73       33.00
         20 |         47        4.31       37.31
         21 |         14        1.28       38.59
         22 |         21        1.92       40.51
         23 |         17        1.56       42.07
         24 |         26        2.38       44.45
         25 |         33        3.02       47.48
         26 |         16        1.47       48.95
         27 |         13        1.19       50.14
         28 |         14        1.28       51.42
         29 |         12        1.10       52.52
         30 |         55        5.04       57.56
         31 |         10        0.92       58.48
         32 |          7        0.64       59.12
         33 |          7        0.64       59.76
         34 |         10        0.92       60.68
         35 |         34        3.12       63.79
         36 |          8        0.73       64.53
         37 |         11        1.01       65.54
         38 |         29        2.66       68.19
         39 |         12        1.10       69.29
         40 |         37        3.39       72.69
         41 |         10        0.92       73.60
         42 |         15        1.37       74.98
         43 |         13        1.19       76.17
         44 |          7        0.64       76.81
         45 |         29        2.66       79.47
         46 |         10        0.92       80.38
         47 |          8        0.73       81.12
         48 |         11        1.01       82.13
         49 |          5        0.46       82.58
         50 |         34        3.12       85.70
         51 |         15        1.37       87.08
         52 |         18        1.65       88.73
         53 |         10        0.92       89.64
         54 |         24        2.20       91.84
         55 |         25        2.29       94.13
         56 |         17        1.56       95.69
         57 |         10        0.92       96.61
         58 |         20        1.83       98.44
         59 |         15        1.37       99.82
         99 |          2        0.18      100.00
------------+-----------------------------------
      Total |      1,091      100.00

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