Frequencies for first 10,000 rows of urf_lung variable in natl2005 dataset :

   Acute or |
    Chronic |
       Lung |
  Disease U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         53        0.53        0.53
          2 |      9,824       98.24       98.77
          9 |        123        1.23      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015