I wonder what the percentage is of those delaying the line due to their slowness vs. the need to search out space. The most aisle time I've taken on any flight

I wonder what the percentage is of those delaying the line due to their slowness vs. the need to search out space. The most aisle time I've taken on any flight might be 10 seconds, though most of the time it's zero since I prefer to store my carry-on below the seat when I can.