Frequencies for s5_c3_6 variable in hcris2552_10_2017 dataset :

  number of |
   stations |
    s500000 |
00600 00300 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          3        0.08        0.08
          2 |          2        0.05        0.13
          4 |          1        0.03        0.16
          5 |          1        0.03        0.19
         12 |          1        0.03        0.21
          . |      3,741       99.79      100.00
------------+-----------------------------------
      Total |      3,749      100.00

by Jean Roth , jroth@nber.org , 25 Oct 2018