The table gives information about the average selling price of a new car over a period of five months. The table also gives some of the chain base index numbers, correct to 1 decimal place, for this information.
| April | May | June | July | August | |
|---|---|---|---|---|---|
| Average price (£) | 28 624 | 28 777 | 28 860 | 28 973 | 29 132 |
| Chain base index number | 100.5 | 100.3 |
Explain what the value 100.3 in the table represents.
Calculate, to 1 decimal place, the chain base index numbers for July and August, and write them in the table.