Frequencies for first 10,000 rows of su variable in nhamcsopd1993 dataset :

   hospital |
   sampling |
  unit code |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,967       19.67       19.67
          2 |      1,401       14.01       33.68
          3 |      1,685       16.85       50.53
          4 |        831        8.31       58.84
          5 |        570        5.70       64.54
          7 |        149        1.49       66.03
          8 |        122        1.22       67.25
          9 |        397        3.97       71.22
         10 |        156        1.56       72.78
         11 |        102        1.02       73.80
         12 |        365        3.65       77.45
         13 |        259        2.59       80.04
         14 |        276        2.76       82.80
         15 |        202        2.02       84.82
         16 |        311        3.11       87.93
         21 |         61        0.61       88.54
         22 |        300        3.00       91.54
         31 |        217        2.17       93.71
         35 |        141        1.41       95.12
         37 |        237        2.37       97.49
         68 |        144        1.44       98.93
         70 |        107        1.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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