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

   Provider |
 PPS Period |
  (Not Used |
      as of |
    4/1/91) |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,398       93.98       93.98
          0 |        602        6.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 24 Sep 2018