"Unchanged" compares today's Top 10 against our earliest tracked snapshot within the last 30 days, growing closer to a full 30-day lookback as more history accumulates. "Days held" counts how many of the tracked days each app appeared anywhere in that chart's Top 10, out of every day history exists for — a newer addition to the tracked window will naturally show a lower fraction even if it's held the top spot every single day since. Free tends to churn fast (new viral hits displacing yesterday's); Grossing tends to be far stickier (established live-service games with entrenched spend) — this page is built to make that contrast visible, not to imply one chart is "better."