Table of 5 is the consensus group size

tl:dr; 4-5 players appears as the common group size even where more players available in friend circle or gaming club

Older surveys asked how many people were in the broader circle of friends or club members which suggested a larger number of players at a table.

Multiple surveys across forums, from twitter and as academic research indicate table sizes of 4-5 players.

Comparing this to the older figures for gaming clubs and friend circles it implies there was a single table running at a time amongst most groups with the suggestion that second tables of typical size for most groups would share players as ~80% of groups were 8px or smaller and would not have fitted a second concurrent table or more than 4 players.

Another interesting note is that 4-5 players breaks across the 'weak/average' threshold for most Adventurers League games - 5 players of equivalent APL to the adventure will find the challenge average, 3-4 players will be weak. This implies that many DMs are having to tune this adventures from 'as written' before being able to run them.

An additional point could be that the 'ideal group size' identified from the Kind DM twitter survey is smaller than most players actual tables (as measured directly by the subclasses survey and Trygstads thesis) implying many players are at ~5 person tables and would prefer to be at 4 person tables.