What were the opening and closing prices of the S&P/ASX 200 Index (AS51) in Australia on December 18, 2024? What was the percentage change? Please round the answers to two decimal places.

```reference [{"type":"table-json","id":2}] ``` Summary: For December 18 2024, the S&P/ASX 200 opened at 8 309.40 and closed at 8 168.20, resulting in a −1.70 % daily change. The figures were obtained from the historical price record for the index on that date .