Frequencies for first 10,000 rows of prov2615 variable in pos1991 dataset :

   calendar |
  year test |
     volume |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,703       97.03       97.03
         90 |        297        2.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016