Frequencies for first 10,000 rows of pps_period variable in psfhos201404 dataset :

   Provider |
 PPS Period |
  (Not Used |
      as of |
    4/1/91) |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,793       97.93       97.93
          0 |        207        2.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 Feb 2018