The reported decline in sales is a direct reflection of the company's performance and is likely to be viewed negatively by investors. A decrease in revenue of this magnitude can often lead to a decrease in stock price, as it may signal underlying issues with demand or competitiveness. The high relevance score is due to the news being specifically about UMC's financial performance, and the importance is high because revenue figures are a critical factor in assessing a company's health. The confidence level is not at 100 because market reactions can be unpredictable and may also be influenced by external factors not mentioned in the article.