Expenditure on the network as a whole, including new construction, improvements and routine maintenance, for each year is as follows.YearSpend (£ million)1979-80831980-81911981-821041982-831101983-841061984-851191985-861191986-871151987-881301988-891311989-901631990-911991991-922011992-932301993-942311994-952471995-962251996-972031997-981771998-991561999-20...