Frequencies for first 10,000 rows of su variable in nhamcsed2002 dataset :

   hospital |
   sampling |
unit marker |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      8,077       80.77       80.77
          2 |        913        9.13       89.90
          3 |        386        3.86       93.76
          4 |        276        2.76       96.52
          5 |        128        1.28       97.80
          6 |        125        1.25       99.05
          7 |         58        0.58       99.63
          8 |         37        0.37      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016