Frequencies for pmcarr_i1 variable in parkwork dataset :

       mcid |
    issuing |
  authority |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        910       83.41       83.41
          6 |         14        1.28       84.69
         13 |          1        0.09       84.78
         23 |          1        0.09       84.88
         39 |          1        0.09       84.97
         45 |          1        0.09       85.06
         51 |          2        0.18       85.24
         57 |         87        7.97       93.22
         58 |          2        0.18       93.40
         77 |         16        1.47       94.87
         88 |         43        3.94       98.81
         99 |         13        1.19      100.00
------------+-----------------------------------
      Total |      1,091      100.00

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