My guiding question was: How have stock market values in High Income Countries changed over time, and what do decade averages show? From the yearly data, I found that stock markets in high income countries have shown long-term growth, although there are clear periods of volatility. When I averaged the data by decade, the pattern became clearer: each decade shows different growth dynamics, with some decades standing out for stronger increases. The line charts helped me see both the year-to-year fluctuations and the overall decade trends. Together, they show the importance of looking at data in different levels of detail.