Sorry to say this, but I suggest you redo your poll.
Considering 4-5 PCs in a group, having or not having a particular class in a campaign is not indicative of anything at all.
Limiting it by level, which may or may not be reached is absolutely arbitrary since it has nothing in the slightest to do with what classes are played, and more about the length of the campaign, the frequency of play, and the pace of advancement. This does NOT give you the goal of "only 'serious' characters".
Limiting it further by arbitrarily disallowing a number of subclassess and feats to meet your "non-magical" criteria that wasn't part of the "generally people don't see fighters" thesis further harms the data.
This poll is extremely flawed and any information from it would be more like harmful misinformation that anything useful. It can only lead to bad data, using it is actively detrimental to any discussion.