Frequencies for first 10,000 rows of quarterbegindate variable in sdued1991 dataset :

    Quarter |
 Begin Date |      Freq.     Percent        Cum.
------------+-----------------------------------
 01/01/1991 |      4,252       42.52       42.52
 04/01/1991 |      4,894       48.94       91.46
 07/01/1991 |        854        8.54      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Feb 2018