Frequencies for first 10,000 rows of importdate variable in bencs2017 dataset :

        Import Date |      Freq.     Percent        Cum.
--------------------+-----------------------------------
2016-05-16 23:14:35 |        270        2.70        2.70
2016-06-01 23:04:04 |         18        0.18        2.88
2016-06-24 02:40:05 |          9        0.09        2.97
2016-06-29 04:36:58 |         81        0.81        3.78
2016-07-01 08:12:23 |        363        3.63        7.41
2016-08-04 02:29:22 |         18        0.18        7.59
2016-08-16 03:04:39 |         90        0.90        8.49
2016-08-18 02:41:03 |        108        1.08        9.57
2016-08-20 07:40:33 |      2,229       22.29       31.86
2016-08-21 04:30:14 |        180        1.80       33.66
2016-08-23 02:28:31 |        243        2.43       36.09
2016-08-24 02:30:21 |      4,083       40.83       76.92
2016-10-19 02:44:25 |      2,014       20.14       97.06
2017-01-19 02:20:17 |        294        2.94      100.00
--------------------+-----------------------------------
              Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 8 Dec 2017