test=# select c1, count(*) as c2 from (select count(*) as c1 from tmp_r group by documentinternalid) foo group by c1;
    c1    |    c2 
----------+-------
        1 | 67884
        2 | 33033
        3 |  9478
        4 | 11205
        5 |  2725
        6 |  3457
        7 |   677
        8 |  1992
        9 |   961
       10 |   857
       11 |   199
       12 |  1397
       13 |    81
       14 |   289
       15 |   630
       16 |   561
       17 |    69
       18 |   360
       19 |    42
       20 |   367
       21 |   232
       22 |   121
       23 |    49
       24 |   380
       25 |   113
       26 |    85
       27 |    93
       28 |   117
       29 |    21
       30 |   136
       31 |    32
       32 |   102
       33 |    24
       34 |    17
       35 |    24
       36 |   145
       37 |    37
       38 |    15
       39 |    17
       40 |    54
       41 |    15
       42 |    65
       43 |     8
       44 |    48
       45 |    26
       46 |    12
       47 |     5
       48 |    88
       49 |    80
       50 |    26
       51 |    10
       52 |    10
       53 |     1
       54 |    68
       55 |     6
       56 |    31
       57 |     6
       58 |     7
       59 |     3
       60 |    43
       61 |     1
       62 |     5
       63 |     7
       64 |    24
       65 |    10
       66 |    24
       68 |     8
       69 |     2
       70 |     9
       71 |     2
       72 |    31
       76 |     7
       77 |     5
       78 |     7
       79 |     3
       80 |    22
       81 |     7
       82 |     4
       84 |    26
       85 |     2
       86 |     4
       88 |     6
       90 |    17
       91 |     5
       94 |     5
       96 |    23
       98 |    86
       99 |     9
      100 |     5
      102 |     2
      104 |     5
      105 |     2
      106 |     1
      108 |    12
      110 |    17
      112 |     6
      113 |     1
      114 |     9
      120 |     6
      121 |     8
      122 |     1
      124 |    10
      126 |     3
      128 |     6
      129 |     2
      132 |    10
      135 |     2
      136 |     1
      138 |     2
      140 |     2
      142 |     1
      144 |     9
      146 |     1
      147 |    15
      148 |     2
      150 |     5
      152 |     4
      154 |     2
      156 |     3
      158 |     1
      160 |     9
      162 |     3
      168 |     2
      174 |     3
      176 |     3
      177 |     1
      178 |     1
      180 |     4
      181 |     2
      183 |     1
      186 |     2
      188 |     5
      192 |     2
      194 |     4
      196 |    35
      198 |     2
      200 |     3
      208 |     4
      213 |     1
      216 |     4
      220 |     2
      223 |     2
      224 |     9
      227 |     1
      228 |     4
      234 |     1
      240 |     4
      241 |     1
      245 |     9
      248 |     1
      252 |     5
      256 |     7
      268 |     1
      272 |     3
      280 |     2
      282 |     1
      283 |     3
      288 |     4
      294 |    24
      300 |     1
      311 |     1
      315 |     1
      320 |     2
      336 |     4
      343 |     1
      352 |     1
      356 |     5
      357 |     2
      360 |     2
      372 |     2
      375 |     1
      378 |     1
      384 |     3
      392 |     9
      393 |     1
      396 |     2
      400 |     3
      403 |     1
      405 |     1
      418 |     1
      432 |     3
      441 |    11
      442 |     1
      443 |     1
      448 |     2
      450 |     1
      454 |     1
      456 |     2
      462 |     2
      475 |     1
      476 |     1
      480 |     2
      488 |     2
      490 |     6
      495 |     1
      500 |     3
      508 |     1
      510 |     1
      512 |     6
      532 |     2
      537 |     1
      540 |     1
      560 |     2
      568 |     1
      576 |     3
      588 |     6
      594 |     1
      600 |     1
      602 |     1
      612 |     1
      614 |     1
      615 |     1
      618 |     2
      621 |     1
      624 |     1
      625 |     1
      636 |     1
      638 |     1
      640 |     1
      643 |     1
      648 |     2
      651 |     1
      672 |     1
      686 |     3
      693 |     1
      696 |     1
      703 |     1
      708 |     6
      714 |     1
      719 |     1
      720 |     2
      725 |     1
      729 |     1
      750 |     1
      756 |     3
      768 |     2
      784 |     3
      788 |     1
      792 |     2
      800 |     2
      816 |     1
      819 |     1
      828 |     1
      833 |     1
      834 |     1
      837 |     1
      850 |     1
      853 |     1
      882 |     7
      900 |     1
      925 |     1
      972 |     1
      980 |     2
      992 |     1
     1000 |     3
     1025 |     1
     1026 |     1
     1029 |     1
     1080 |     1
     1100 |     1
     1150 |     1
     1152 |     3
     1175 |     1
     1176 |     7
     1184 |     1
     1200 |     1
     1225 |     1
     1280 |     1
     1296 |     1
     1314 |     1
     1323 |     2
     1332 |     1
     1350 |     2
     1372 |     1
     1374 |     1
     1392 |     1
     1440 |     1
     1520 |     2
     1536 |     1
     1566 |     1
     1632 |     3
     1708 |     1
     1715 |     1
     1728 |     1
     1764 |     2
     1800 |     4
     1824 |     1
     1933 |     5
     2016 |     2
     2052 |     1
     2112 |     1
     2401 |    17
     2538 |     1
     2560 |     1
     2736 |     1
     2744 |     1
     2808 |     1
     2856 |     1
     2916 |     1
     3000 |     3
     3087 |     1
     3096 |     2
     3171 |     1
     3200 |     1
     3400 |     2
     3408 |     1
     3456 |     2
     3560 |     1
     3726 |     1
     3801 |     1
     3840 |     1
     3866 |     1
     3920 |     1
     3968 |     1
     4116 |     1
     4704 |     1
     4736 |     1
     4802 |    18
     5376 |     1
     5831 |     1
     6174 |     2
     6208 |     1
     6480 |     1
     6784 |     1
     6912 |     1
     7203 |     5
     7272 |     1
     7889 |     1
     8019 |     1
     9261 |     1
     9604 |    12
     9900 |     1
    10290 |     2
    10496 |     1
    10976 |     3
    11264 |     1
    11328 |     1
    12005 |     1
    12250 |     1
    13412 |     1
    14406 |     4
    15435 |     1
    17150 |     1
    17493 |     2
    19208 |     3
    20160 |     1
    21168 |     1
    22748 |     1
    24010 |     2
    24696 |     3
    26754 |     1
    28730 |     1
    28812 |     3
    30380 |     1
    30492 |     1
    33271 |     1
    35672 |     1
    36015 |     1
    36358 |     1
    37044 |     1
    38416 |     4
    39102 |     1
    41160 |     1
    43218 |     2
    43904 |     4
    44247 |     1
    45056 |     1
    46080 |     1
    46648 |     1
    48640 |     1
    49392 |     3
    50764 |     2
    57624 |     6
    63112 |     2
    70800 |     1
    71344 |     2
    74088 |     1
    76832 |     1
    78204 |     1
    87808 |     1
    92610 |     1
    93296 |     1
    96726 |     1
   100864 |     1
   101528 |     1
   105644 |     1
   113876 |     1
   115248 |     1
   120736 |     1
   123480 |     1
   129654 |     1
   137200 |     1
   149548 |     1
   170128 |     3
   180075 |     1
   192080 |     1
   197568 |     1
   203056 |     2
   205800 |     1
   238728 |     1
   251076 |     1
   260680 |     1
   262395 |     1
   268912 |     1
   273616 |     1
   274400 |     3
   279888 |     2
   288120 |     3
   303212 |     1
   351575 |     1
   378672 |     1
   384160 |     3
   391363 |     1
   417088 |     1
   419832 |     1
   432180 |     1
   488775 |     1
   543312 |     1
   637980 |     2
   696192 |     1
   744996 |     1
   864768 |     1
   957999 |     1
   971376 |     1
   998816 |     1
  1004304 |     1
  1531152 |     1
  2092300 |     1
  2185596 |     1
  2370816 |     1
  2667168 |     1
  2823576 |     1
  2915500 |     1
  5299350 |     1
  7271600 |     1
  7310016 |     1
  9730224 |     1
 10515008 |     3
 12348000 |     1
(439 rows)