depending on how you count, tfl may be responsible for >50% of total passengers on uk rail https://en.wikipedia.org/wiki/List_of_countries_by_rail_usage#:~:text=The%20London%20Underground%20%28%22The%20Tube%22%29%20had%20an%20additional%201%2E34%20billion%20passengers%20in%202015...
