Frequencies for psp_use variable in parkwork dataset :

special use |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,121       98.94       98.94
          1 |          1        0.09       99.03
          2 |          2        0.18       99.21
          3 |          2        0.18       99.38
          5 |          3        0.26       99.65
         13 |          2        0.18       99.82
         99 |          2        0.18      100.00
------------+-----------------------------------
      Total |      1,133      100.00

by Jean Roth , jroth@nber.org , 22 Oct 2016