Frequencies for first 10,000 rows of stratm variable in namcs1998 dataset :

psu stratum |
     marker |
   (masked) |      Freq.     Percent        Cum.
------------+-----------------------------------
        201 |      1,236       12.36       12.36
        202 |      1,235       12.35       24.71
        203 |      1,034       10.34       35.05
        204 |      1,159       11.59       46.64
        401 |        869        8.69       55.33
        402 |      1,262       12.62       67.95
        403 |      2,129       21.29       89.24
        404 |      1,076       10.76      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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