I did some work using Census 2011 data and created league tables for modes of transport across England and Wales. 56% of London residents commute to work by public transport. Next highest is Manchester at 31%. Unsure where that stands within an international league. I'd assume Tokyo would be higher.
https://docs.google.com/spreadsheets/d/1U9f-g8ETvljw-YAZbFpW...
With another ~15% for cycling/walking for London, it's an amazingly easy city to get around with transport options that stretch out far from the city itself (I travel 50 miles each way, taking 1hr15m when everything is working correctly).
I think the more interesting work I did was around the 20 min walk/20min cycle and the numbers of people still driving those distances. In London 164,079 within 20 minute walk, 584,749 within 20 minute cycle out of a total of 1,097,173 people that drive.
I'm in the process of writing this up but the implication is that we could get a large reduction in congestion and traffic pollution through building a good cycle network.
More interestingly we should probably move to a road charging system that dispraportionatly charges high for short car journeys.