7 Table 3.11 shows the index numbers associated with transport costs during a 20 -year period. The public transport costs reflect changes to bus and train fares, whereas private transport costs include purchase, service, petrol, tax and insurance costs of cars. (1) Which year is chosen as the base year? (2) Find the percentage increases in the cost of public transport from (a) 1985 to 1990 (b) 1990 to 1995 (c) 1995 to 2000 (d) 2000 to 2005 (3) Repeat part (2) for private transport. (4) Comment briefly on the relative rise in public and private transport costs during this 20 -year period