Frequencies for s5_c4_6 variable in hcris2552_10_2010 dataset :

  number of |
   stations |
    s500000 |
00600 00400 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          7        0.30        0.30
          2 |          3        0.13        0.43
          3 |          1        0.04        0.47
          4 |          1        0.04        0.52
          6 |          2        0.09        0.60
          7 |          1        0.04        0.65
          . |      2,307       99.35      100.00
------------+-----------------------------------
      Total |      2,322      100.00

by Jean Roth , jroth@nber.org , 23 Aug 2018