Frequencies for first 10,000 rows of cstratm variable in nhamcsopd2010 dataset :

  clustered |
psu stratum |
   marker - |
     masked |      Freq.     Percent        Cum.
------------+-----------------------------------
   2.01e+07 |      1,800       18.00       18.00
   2.02e+07 |        210        2.10       20.10
   2.03e+07 |        757        7.57       27.67
   2.04e+07 |        700        7.00       34.67
   4.01e+07 |      1,711       17.11       51.78
   4.02e+07 |      1,977       19.77       71.55
   4.03e+07 |      2,182       21.82       93.37
   4.04e+07 |        663        6.63      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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