Frequencies for pem_use variable in parkwork dataset :

  Emergency |
        Use |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        997       99.50       99.50
          1 |          5        0.50      100.00
------------+-----------------------------------
      Total |      1,002      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016