When was the peak demand reached according to the provided data?

The peak demand is identified as the highest level of demand within a specific timeframe. In examining the details, August 1998 is noted for its outstanding demand levels compared to other months or years referenced. This indicates that during this period, the conditions—such as temperature, economic activity, and energy consumption patterns—led to it being a time of elevated utility demand.

The other timeframes listed did not match the demand levels observed in August 1998, suggesting that while they may have represented significant demand periods, they did not surpass the peak identified during that month. Thus, August 1998 is recognized as the peak demand period based on the data provided.