At the end of July, Google announced that they would no longer identify Web pages in the Supplemental Index. Although such pages have reduced visibility in Google’s keyword search results, Google felt that the Supplemental label was attracting undue attention. In any case, there would be greater efforts to reduce the disparity between the Google regular index and the Google supplemental index.
Danny Sullivan and many others expressed concern about this move. However there was still a loophole as Danny mentioned:
At the moment, if you want to force the labels to show up, doing a search for [site:domain/&] is a tip that came out of WebmasterWorld this week, and that still seems to be still working.
It now appears that the loophole has been closed. A Google search for site:www.domain.com/& shows exactly the same number of web pages as the recommended Google search for site:www.domain.com/. In other words, both show the total number of web pages that Google has indexed in both the regular index and the supplemental index.
For the moment, the other trick that Halfdeck mentioned seems still to be working. A search for site:www.domain.com/* still seems to give the number of web pages that are in the regular index. Comparing this with the total number of web pages indicated by the regular site:www.domain.com/ can give an indication of what percentage of the total web pages on the domain are in the regular index. For established websites this is often above 75%. For new websites on the other hand, less than 20% of web pages seem to be in the regular index if this test is valid.
Is this a reasonable estimate? If so, how long will Google leave this peephole open? Time will tell.