Frequencies for first 10,000 rows of cstratm variable in nhamcsed2004 dataset :

  clustered |
psu stratum |
     marker |
   (masked) |      Freq.     Percent        Cum.
------------+-----------------------------------
   2.01e+07 |      1,660       16.60       16.60
   2.02e+07 |        914        9.14       25.74
   2.03e+07 |      1,130       11.30       37.04
   2.04e+07 |        973        9.73       46.77
   4.01e+07 |        673        6.73       53.50
   4.02e+07 |      1,040       10.40       63.90
   4.03e+07 |      2,732       27.32       91.22
   4.04e+07 |        878        8.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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