Frequencies for first 10,000 rows of refer variable in namcs2015 dataset :

Was patient |
   referred |
 for visit? |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |        144        1.44        1.44
         -8 |      1,025       10.25       11.69
         -7 |      2,543       25.43       37.12
          1 |      2,285       22.85       59.97
          2 |      4,003       40.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 25 Oct 2017