The line graph illustrates the distribution of those UK citizens, who used various vehicles regularly, such as cars, buses and trains over the last sixty years (between 1970 and 2030 to be precise).
To summarize, the overall upward trend correlated to car drivers and train passengers, whereas for commuters, preferring buses as their main transport, a steady downward was registered during the whole time frame discussed.
A closer examination of the car and train figures reveals a very similar tendency. Thus, they both experienced a great surge throughout the last three decades of the second millennium: car drivers increased to 7 millions, while train users to 3 at the outset of the XXI century. Then those, choosing the private transport more frequently, as well as the train passengers, reached the plateau and remained the same for at least ten years. Afterwards, there was the sharp growth from early 2010-x, which ended up with the peak of around 9 millions for the car drivers and 4 millions for the train users.
Looking at citizens who gave the preference to the bus, their statistics, starting from nearly 2 millions in 1970, dropped steadily by around 3 millions in 2030. To compare this figure with two former, it is clear that changes in the bus commuters were rather smoother and substantial, than concerning the train or self-driving proportion.