Frequencies for first 10,000 rows of urf_lung variable in natl2004 dataset :

   Acute or |
    Chronic |
       Lung |
  Disease U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         62        0.62        0.62
          2 |      8,957       89.57       90.19
          9 |        981        9.81      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 21 Jan 2016