Frequencies for pem_use variable in parkwork dataset :

  emergency |
        use |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,088       99.73       99.73
          1 |          3        0.27      100.00
------------+-----------------------------------
      Total |      1,091      100.00

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