51% used the DLR in 2011. Apparantly not one passengers caught a bus. Remember in a lot of analysis done by other airports, black cabs count as public transport too!
http://www.londoncityairport.com/con...PAX_Access.pdf
The DLR figure has since risen to well above 60% I believe. Next time you are travelling through LCY, when you go up the esculator to security, it is one of the "fun stats" that are on the walls. When crossrail opens at Canning town, maybe the figure will approach 75%.
A friend who works there told me the jewellery store (on average) actually has a very good taking, for often only 1 member of staff overhead. At quiter times of the day, Neros has lots of staff and no-one to serve. There are other coffee shops before and after security too. But once the expansion of departures is complete hopefully they'll be more space for everyone.