The table displays information on the underground railway systems across six cities, including the years they were established.
On the whole, what stands out from the table is that Paris had the largest number of passengers per year, while Tokyo was in second and London was in third place. In contrast, other remaining cities had a way lower volume of commuters.
In 1863, London initially was the most mature underground with a length of 394 killometres, which had 775 million travelers annually. In 1900, Paris underground outnumbered London with the higher fraction of customers, while it was 199 kilometers in length. Despite that, in 1927, the new record was set by Tokyo, which had 1927 customers each year with 155 kilometers of route.
Three countries had the smallest proportion of visitors. In 1976, Washington DC was 126 kilometres long in distance and the customer number was 144 million every year. Kyoto was the smallest in terms of length as well as passengers, which was 11 kilometers long and had 45 million people. In 2001, Los Angeles had 50 million commuters with 28 kilometers of length.