A statistic is a number displayed to summarize something people may want to know. It is like a scoreboard that puts the most useful total where you can see it quickly.
For example, a project page might show how many tasks are finished. A helpful statistic usually has a short label, such as “Tasks completed,” so the number does not have to explain itself.
Choose numbers that help someone understand a situation or make a decision. If the meaning or time period is unclear, add a few words of context rather than showing a number by itself.